Update extension README, detailing new factories integration.
Update extension README, detailing new factories integration.

Related to #2780

FadliKun/spree,beni55/spree,rajeevriitm/spree,mindvolt/spree,builtbybuffalo/spree,pervino/spree,gautamsawhney/spree,kewaunited/spree,Hawaiideveloper/shoppingcart,Boomkat/spree,omarsar/spree,agient/agientstorefront,pulkit21/spree,nooysters/spree,CJMrozek/spree,ramkumar-kr/spree,locomotivapro/spree,TrialGuides/spree,Mayvenn/spree,siddharth28/spree,softr8/spree,thogg4/spree,softr8/spree,welitonfreitas/spree,robodisco/spree,scottcrawford03/solidus,pjmj777/spree,berkes/spree,bjornlinder/Spree,dafontaine/spree,project-eutopia/spree,ayb/spree,gregoryrikson/spree-sample,vcavallo/spree,fahidnasir/spree,DynamoMTL/spree,xuewenfei/solidus,jordan-brough/spree,rakibulislam/spree,kitwalker12/spree,scottcrawford03/solidus,nooysters/spree,volpejoaquin/spree,groundctrl/spree,brchristian/spree,pulkit21/spree,pervino/solidus,shaywood2/spree,vmatekole/spree,reidblomquist/spree,yushine/spree,pervino/spree,mleglise/spree,Lostmyname/spree,volpejoaquin/spree,Antdesk/karpal-spree,jparr/spree,DarkoP/spree,jeffboulet/spree,athal7/solidus,TrialGuides/spree,karlitxo/spree,zamiang/spree,vinsol/spree,imella/spree,Ropeney/spree,njerrywerry/spree,KMikhaylovCTG/spree,wolfieorama/spree,omarsar/spree,athal7/solidus,raow/spree,Kagetsuki/spree,orenf/spree,dotandbo/spree,Senjai/spree,KMikhaylovCTG/spree,karlitxo/spree,edgward/spree,pervino/spree,shekibobo/spree,scottcrawford03/solidus,JDutil/spree,firman/spree,nooysters/spree,dafontaine/spree,sfcgeorge/spree,richardnuno/solidus,locomotivapro/spree,robodisco/spree,TimurTarasenko/spree,lsirivong/spree,useiichi/spree,Hates/spree,AgilTec/spree,tesserakt/clean_spree,Machpowersystems/spree_mach,CiscoCloud/spree,patdec/spree,tesserakt/clean_spree,maybii/spree,locomotivapro/spree,derekluo/spree,ujai/spree,CiscoCloud/spree,LBRapid/spree,jaspreet21anand/spree,Hates/spree,abhishekjain16/spree,jeffboulet/spree,tomash/spree,lsirivong/solidus,mleglise/spree,shioyama/spree,progsri/spree,hoanghiep90/spree,maybii/spree,piousbox/spree,Engeltj/spree,dandanwei/spree,omarsar/spree,ayb/spree,assembledbrands/spree,alejandromangione/spree,jordan-brough/spree,piousbox/spree,rajeevriitm/spree,sunny2601/spree,kitwalker12/spree,jimblesm/spree,delphsoft/spree-store-ballchair,Engeltj/spree,jasonfb/spree,welitonfreitas/spree,yushine/spree,ayb/spree,robodisco/spree,StemboltHQ/spree,jeffboulet/spree,edgward/spree,edgward/spree,LBRapid/spree,scottcrawford03/solidus,rbngzlv/spree,bonobos/solidus,Senjai/solidus,vinsol/spree,adaddeo/spree,pervino/spree,quentinuys/spree,JuandGirald/spree,carlesjove/spree,wolfieorama/spree,APohio/spree,lsirivong/spree,tancnle/spree,lyzxsc/spree,tesserakt/clean_spree,locomotivapro/spree,vulk/spree,HealthWave/spree,Hates/spree,orenf/spree,degica/spree,Nevensoft/spree,urimikhli/spree,ayb/spree,priyank-gupta/spree,Hawaiideveloper/shoppingcart,njerrywerry/spree,zaeznet/spree,archSeer/spree,mleglise/spree,yushine/spree,jspizziri/spree,Machpowersystems/spree_mach,archSeer/spree,TrialGuides/spree,fahidnasir/spree,joanblake/spree,derekluo/spree,Lostmyname/spree,delphsoft/spree-store-ballchair,vinayvinsol/spree,zamiang/spree,omarsar/spree,JuandGirald/spree,Arpsara/solidus,shaywood2/spree,ahmetabdi/spree,Hawaiideveloper/shoppingcart,madetech/spree,radarseesradar/spree,hifly/spree,ckk-scratch/solidus,CiscoCloud/spree,grzlus/solidus,urimikhli/spree,carlesjove/spree,degica/spree,vmatekole/spree,xuewenfei/solidus,biagidp/spree,keatonrow/spree,kewaunited/spree,tancnle/spree,alejandromangione/spree,robodisco/spree,priyank-gupta/spree,CiscoCloud/spree,ckk-scratch/solidus,devilcoders/solidus,delphsoft/spree-store-ballchair,pjmj777/spree,dandanwei/spree,vcavallo/spree,thogg4/spree,rbngzlv/spree,vulk/spree,patdec/spree,sliaquat/spree,Senjai/spree,azranel/spree,miyazawatomoka/spree,grzlus/spree,jasonfb/spree,Kagetsuki/spree,reinaris/spree,adaddeo/spree,calvinl/spree,Ropeney/spree,odk211/spree,yiqing95/spree,reidblomquist/spree,volpejoaquin/spree,caiqinghua/spree,APohio/spree,bricesanchez/spree,kewaunited/spree,grzlus/spree,watg/spree,vulk/spree,biagidp/spree,azranel/spree,firman/spree,mindvolt/spree,jeffboulet/spree,raow/spree,quentinuys/spree,jspizziri/spree,HealthWave/spree,DynamoMTL/spree,hifly/spree,Mayvenn/spree,ahmetabdi/spree,rakibulislam/spree,reidblomquist/spree,rakibulislam/spree,jhawthorn/spree,FadliKun/spree,ramkumar-kr/spree,pjmj777/spree,cutefrank/spree,mindvolt/spree,xuewenfei/solidus,moneyspyder/spree,fahidnasir/spree,gregoryrikson/spree-sample,Lostmyname/spree,bonobos/solidus,NerdsvilleCEO/spree,assembledbrands/spree,azranel/spree,edgward/spree,APohio/spree,jsurdilla/solidus,PhoenixTeam/spree_phoenix,hoanghiep90/spree,Arpsara/solidus,siddharth28/spree,useiichi/spree,jparr/spree,shekibobo/spree,StemboltHQ/spree,beni55/spree,imella/spree,ahmetabdi/spree,DarkoP/spree,AgilTec/spree,groundctrl/spree,sunny2601/spree,Boomkat/spree,lsirivong/solidus,NerdsvilleCEO/spree,alvinjean/spree,alejandromangione/spree,reinaris/spree,woboinc/spree,athal7/solidus,groundctrl/spree,HealthWave/spree,yiqing95/spree,quentinuys/spree,Antdesk/karpal-spree,assembledbrands/spree,tomash/spree,jsurdilla/solidus,PhoenixTeam/spree_phoenix,lyzxsc/spree,beni55/spree,APohio/spree,biagidp/spree,dandanwei/spree,radarseesradar/spree,Lostmyname/spree,tomash/spree,jparr/spree,brchristian/spree,sliaquat/spree,rajeevriitm/spree,gautamsawhney/spree,rbngzlv/spree,vcavallo/spree,pulkit21/spree,reinaris/spree,sideci-sample/sideci-sample-spree,degica/spree,camelmasa/spree,SadTreeFriends/spree,tancnle/spree,SadTreeFriends/spree,priyank-gupta/spree,orenf/spree,Nevensoft/spree,brchristian/spree,PhoenixTeam/spree_phoenix,net2b/spree,JuandGirald/spree,firman/spree,dandanwei/spree,AgilTec/spree,vinsol/spree,jsurdilla/solidus,freerunningtech/spree,vinayvinsol/spree,CJMrozek/spree,trigrass2/spree,sideci-sample/sideci-sample-spree,zamiang/spree,bricesanchez/spree,progsri/spree,radarseesradar/spree,shaywood2/spree,builtbybuffalo/spree,Migweld/spree,LBRapid/spree,knuepwebdev/FloatTubeRodHolders,odk211/spree,gregoryrikson/spree-sample,softr8/spree,ckk-scratch/solidus,yushine/spree,miyazawatomoka/spree,jspizziri/spree,RatioClothing/spree,jordan-brough/solidus,lsirivong/solidus,fahidnasir/spree,moneyspyder/spree,lyzxsc/spree,njerrywerry/spree,alejandromangione/spree,agient/agientstorefront,piousbox/spree,builtbybuffalo/spree,moneyspyder/spree,raow/spree,Nevensoft/spree,project-eutopia/spree,useiichi/spree,KMikhaylovCTG/spree,hifly/spree,softr8/spree,jordan-brough/solidus,dotandbo/spree,azclick/spree,ujai/spree,net2b/spree,Engeltj/spree,sfcgeorge/spree,DarkoP/spree,builtbybuffalo/spree,sliaquat/spree,TimurTarasenko/spree,rajeevriitm/spree,camelmasa/spree,lsirivong/solidus,alepore/spree,cutefrank/spree,patdec/spree,Senjai/spree,alvinjean/spree,knuepwebdev/FloatTubeRodHolders,miyazawatomoka/spree,calvinl/spree,maybii/spree,jimblesm/spree,Nevensoft/spree,kewaunited/spree,Machpowersystems/spree_mach,zaeznet/spree,FadliKun/spree,Engeltj/spree,yomishra/pce,bjornlinder/Spree,zaeznet/spree,trigrass2/spree,ramkumar-kr/spree,richardnuno/solidus,joanblake/spree,abhishekjain16/spree,Boomkat/spree,sfcgeorge/spree,grzlus/solidus,lsirivong/spree,net2b/spree,azclick/spree,watg/spree,vinayvinsol/spree,vcavallo/spree,calvinl/spree,yomishra/pce,caiqinghua/spree,richardnuno/solidus,vmatekole/spree,devilcoders/solidus,grzlus/solidus,tailic/spree,madetech/spree,TimurTarasenko/spree,wolfieorama/spree,Migweld/spree,ujai/spree,hifly/spree,caiqinghua/spree,cutefrank/spree,Migweld/spree,alepore/spree,shaywood2/spree,pulkit21/spree,Hawaiideveloper/shoppingcart,caiqinghua/spree,keatonrow/spree,project-eutopia/spree,shekibobo/spree,keatonrow/spree,pervino/solidus,mleglise/spree,rakibulislam/spree,hoanghiep90/spree,knuepwebdev/FloatTubeRodHolders,Hates/spree,useiichi/spree,devilcoders/solidus,woboinc/spree,sideci-sample/sideci-sample-spree,jhawthorn/spree,DynamoMTL/spree,patdec/spree,berkes/spree,trigrass2/spree,jhawthorn/spree,lyzxsc/spree,camelmasa/spree,vinsol/spree,freerunningtech/spree,ramkumar-kr/spree,tailic/spree,piousbox/spree,agient/agientstorefront,berkes/spree,athal7/solidus,tesserakt/clean_spree,derekluo/spree,archSeer/spree,bonobos/solidus,watg/spree,azranel/spree,JDutil/spree,jasonfb/spree,FadliKun/spree,jordan-brough/solidus,joanblake/spree,forkata/solidus,surfdome/spree,alvinjean/spree,net2b/spree,delphsoft/spree-store-ballchair,karlitxo/spree,forkata/solidus,vulk/spree,lsirivong/spree,thogg4/spree,agient/agientstorefront,cutefrank/spree,jimblesm/spree,zaeznet/spree,ckk-scratch/solidus,madetech/spree,JDutil/spree,sunny2601/spree,urimikhli/spree,jparr/spree,quentinuys/spree,firman/spree,carlesjove/spree,gautamsawhney/spree,jspizziri/spree,CJMrozek/spree,rbngzlv/spree,abhishekjain16/spree,berkes/spree,surfdome/spree,AgilTec/spree,DarkoP/spree,jaspreet21anand/spree,freerunningtech/spree,thogg4/spree,Senjai/solidus,NerdsvilleCEO/spree,dafontaine/spree,beni55/spree,dotandbo/spree,tomash/spree,joanblake/spree,siddharth28/spree,Kagetsuki/spree,grzlus/spree,imella/spree,progsri/spree,TimurTarasenko/spree,grzlus/solidus,shioyama/spree,xuewenfei/solidus,volpejoaquin/spree,moneyspyder/spree,abhishekjain16/spree,maybii/spree,keatonrow/spree,sliaquat/spree,azclick/spree,derekluo/spree,pervino/solidus,DynamoMTL/spree,forkata/solidus,sfcgeorge/spree,Arpsara/solidus,jordan-brough/solidus,PhoenixTeam/spree_phoenix,surfdome/spree,adaddeo/spree,odk211/spree,nooysters/spree,madetech/spree,trigrass2/spree,JDutil/spree,raow/spree,StemboltHQ/spree,miyazawatomoka/spree,project-eutopia/spree,jordan-brough/spree,pervino/solidus,bricesanchez/spree,orenf/spree,wolfieorama/spree,jaspreet21anand/spree,karlitxo/spree,siddharth28/spree,bonobos/solidus,TrialGuides/spree,jimblesm/spree,tancnle/spree,alepore/spree,richardnuno/solidus,gregoryrikson/spree-sample,yiqing95/spree,radarseesradar/spree,dotandbo/spree,Arpsara/solidus,Ropeney/spree,Senjai/solidus,jasonfb/spree,hoanghiep90/spree,zamiang/spree,SadTreeFriends/spree,welitonfreitas/spree,njerrywerry/spree,mindvolt/spree,camelmasa/spree,grzlus/spree,vmatekole/spree,jsurdilla/solidus,carlesjove/spree,NerdsvilleCEO/spree,odk211/spree,JuandGirald/spree,welitonfreitas/spree,priyank-gupta/spree,Mayvenn/spree,Migweld/spree,surfdome/spree,CJMrozek/spree,sunny2601/spree,SadTreeFriends/spree,yomishra/pce,shekibobo/spree,archSeer/spree,Senjai/solidus,Antdesk/karpal-spree,alvinjean/spree,devilcoders/solidus,woboinc/spree,brchristian/spree,Kagetsuki/spree,Ropeney/spree,vinayvinsol/spree,Mayvenn/spree,yiqing95/spree,gautamsawhney/spree,RatioClothing/spree,azclick/spree,dafontaine/spree,RatioClothing/spree,reinaris/spree,forkata/solidus,kitwalker12/spree,tailic/spree,reidblomquist/spree,progsri/spree,shioyama/spree,adaddeo/spree,groundctrl/spree,calvinl/spree,bjornlinder/Spree,Boomkat/spree,KMikhaylovCTG/spree,jaspreet21anand/spree,ahmetabdi/spree