added better middleware docs and use-cases
added better middleware docs and use-cases

andriyl/express,nodejs-camp/booklog-linkchen,FernAbby/express,coreypnorris/express,ZackBotkin/express,lmtdit/express,ericlu88/express,VegeChou/express,vinodhalaharvi/express,jenia0jenia/express,heicx/express,YR/express,svnh/express,LestaD/express,PeterWangPo/express,microlv/express,strongloop/express,v10258/express,WebStyle/express,supasate/express,1amageek/express,tianhengzhou/express,chuym/express,smcmurray/express,maraoz/express,mauricionr/express,MoraLin/mora-test,hdngr/express,andrejewski/express,xtidt/express,sibura/express,corporateanon/express,xiaofuzi/express,dongseop/express,nodejs-camp/booklog-polo,XueQian/express,v10258/express,PeterWangPo/express,v10258/express,nodejs-camp/booklog-chenyou,kubrickology/express,nodejs-camp/booklog-jollen,methuz/express,Lexine/express,simudream/express,nodejs-camp/booklog-tonebeta,pstrike/express,jinghuizhai/express,featurist/express,fineday32/express,fakedarren/express,CrazySherman/express,KodkodGates/express,luxe-eng/valet-express.express,blakeembrey/express,evilboss/express,bercanozcan/express,r14r-work/fork_express_master,llwanghong/express,stoskov/express,hl198181/express,dreamingblackcat/express,mimaidms/express,kylezhang/express,benshiue/booklog-ben,rgrove/express,mcanthony/express,jimmykuo/express,pshomov/express,kunalpict/express,Kevnz/express,Riokai/express,udhayam/express,micha149/express,frootloops/express,xtidt/express,demohi/express,Riokai/express,ralic/express,cflynn07/express,dongooo/express,friederbluemle/express,gretac/express,hightechweb/express,swstack/express,dsupera13/express,topaxi/express,jenalgit/express,auth0/express,nodejs-camp/booklog-jollen,youprofit/express,demohi/express,vinodhalaharvi/express,grigorkh/express,nbeydoon/express,countdracular/express,nodejs-camp/booklog-Zak,listepo/express,mauricionr/express,nodejs-camp/booklog-Zak,nodejs-camp/booklog-mora,stoskov/express,RickyDan/express,topaxi/express,dreamingblackcat/express,shanawarkhan/express,nodejs-camp/booklog-leo,nodejs-camp/booklog-chenyou,qitianchan/express,xiaofuzi/express,blairzhang/express,nodejs-camp/booklog-tonebeta,adjohnson916/express,coreypnorris/express,fineday32/express,jinghuizhai/express,junxiong/express,corporateanon/express,simudream/express,1verson/express,stevemao/express,christopheranderson/express,hpcslag/express,JulyZhu/express,juandav/express,vidyar/express,thepont/express,Talkyunyun/express,sarvex/express,stewartml/express,JulyZhu/express,drzorm/express,friederbluemle/express,flomotlik/express,jymsy/express,swarajgiri/express,brianloveswords/express,Eric-Vandenberg/express,wtony/express,ZackBotkin/express,rgrove/express,nodejs-camp/booklog-jason,heicx/express,TestingCI/express,nbeydoon/express,vidyar/express,micha149/express,isaacs/express,adjohnson916/express,igarciaes/express,bercanozcan/express,Jonekee/express,nodejs-camp/booklog-ben,Haru1990/express,aifeld/express,nathan818fr/express,KodkodGates/express,Haru1990/express,awronka/express,BaggersIO/express,XueQian/express,mcanthony/express,za-creature/express,qitianchan/express,dafabulousteach/express,pstrike/express,za-creature/express,tyler-johnson/express,bjrmatos/express,gdeividas/express,simplyianm/express,lian774739140/express,ci-test2/express,Kevnz/express,philxia/ex-tst-framework,bercanozcan/express,saisai/express,soyuka/express,blairzhang/express,caiocutrim/express,lian774739140/express,danielrohers/express,listepo/express,dafabulousteach/express,leiqiang75/express,kunalpict/express,1verson/express,hacksparrow/express,PUSEN/express,mimaidms/express,nodejs-camp/booklog-tonebeta-update,awronka/express,junxiong/express,nodejs-camp/booklog-ausir,nodejs-camp/booklog-ben,hanweifish/express,sarvex/express,dongooo/express,svnh/express,RanadeepPolavarapu/express,samuelcastro/express,smcmurray/express,dongseop/express,dafabulousteach/express,wesleytodd/express,neomadara/express,juanpastas/express,WangCao/express,hanqingnan/express,andrejewski/express,TestingCI/express,nodejs-camp/booklog-tonebeta-update,sarvex/express,Faiz7412/express,yinhe007/express,baldurh/express,tjmehta/express,svnh/express,gdeividas/express,dreamingblackcat/express,evilboss/express,junxiong/express,abdulhannanali/express,fuse-mars/express,vnglst/express,za-creature/express,chrisinajar/express,LestaD/express,simudream/express,shanawarkhan/express,weilixia/express,ci-test2/express,nodejs-camp/booklog-ansaga,jimmykuo/express,nbeydoon/express,youprofit/express,WangCao/express,fakedarren/express,btleffler/express,lemelon/express,supasate/express,sujianping/express,nodejs-camp/booklog-ansaga,Ivanwangcy/express,kentcdodds/express,ZackBotkin/express,fanzetao/express,drzorm/express,topaxi/express,pathirana/express,buildsample/express,michaeljunlove/express,smcmurray/express,PUSEN/express,FernAbby/express,nodejs-camp/booklog-archer,gretac/express,ifraixedes/express,dotnetCarpenter/express,lemelon/express,jenia0jenia/express,pshomov/express,abhi3/express,philxia/ex-tst-framework,MoraLin/mora-test,chuym/express,dotnetCarpenter/express,Faiz7412/express,ahdinosaur/express,soyuka/express,devgeniem/express,caiocutrim/express,Matrixbirds/express,srichatala/express,fanzetao/express,blainsmith/express,angelsanz/express,hanqingnan/express,nodejs-camp/booklog-s890506,kylezhang/express,ralic/express,isaacs/express,coreypnorris/express,Flip120/express,qq645381995/express,hdngr/express,stevemao/express,kubrickology/express,Ivanwangcy/express,Flip120/express,neomadara/express,michaeljunlove/express,blainsmith/express,dotnetCarpenter/express,cflynn07/express,hdngr/express,blakeembrey/express,devgeniem/express,angelsanz/express,chrisinajar/express,andriyl/express,kawanet/express,hl198181/express,tyler-johnson/express,dongseop/express,christopheranderson/express,HXYNODE/express,dieuly/express,fakedarren/express,countdracular/express,lmtdit/express,rupanjanbaidya/express,Ju2ender/express,benshiue/booklog-ben,listepo/express,hpcslag/express,featurist/express,methuz/express,mikewesthad/express,abhi3/express,vinodhalaharvi/express,qq645381995/express,codeforgeek/express,Jonekee/express,mikewesthad/express,Flip120/express,philxia/ex-tst-framework,supasate/express,robomc/express,sibura/express,baldurh/express,ericlu88/express,ci-test2/express,luxe-eng/valet-express.express,luxe-eng/valet-express.express,simplyianm/express,qitianchan/express,dieuly/express,Faiz7412/express,nodejs-camp/booklog-chle,hanweifish/express,jenia0jenia/express,XueQian/express,nodejs-camp/booklog-jason,stewartml/express,TestingCI/express,RanadeepPolavarapu/express,evanlucas/express,nodejs-camp/booklog-homa,frootloops/express,tianhengzhou/express,r14r/fork_express_master,gnowoel/express,Ju2ender/express,yinhe007/express,lmtdit/express,buildsample/express,danielrohers/express,udhayam/express,nodejs-camp/booklog-s890506,microlv/express,Riokai/express,Eric-Vandenberg/express,philxia/ex-tst-framework,KodkodGates/express,CrazySherman/express,angelsanz/express,ahdinosaur/express,jenalgit/express,devgeniem/express,corporateanon/express,hacksparrow/express,qq645381995/express,nodejs-camp/booklog-polo,WangCao/express,vnglst/express,emvici/emvici-reqres-tify,swstack/express,rupanjanbaidya/express,VegeChou/express,nodejs-camp/booklog-chle,nodejs-camp/booklog-archer,hightechweb/express,srichatala/express,nodejs-camp/booklog-mora,elkingtonmcb/express,chrisinajar/express,sujianping/express,juandav/express,pathirana/express,wesleytodd/express,bjrmatos/express,nodejs-camp/booklog-polo,saisai/express,friederbluemle/express,abhi3/express,Talkyunyun/express,kentcdodds/express,swarajgiri/express,blairzhang/express,robomc/express,Eric-Vandenberg/express,youprofit/express,r14r/fork_express_master,nodejs-camp/booklog-leo,samuelcastro/express,Matrixbirds/express,vnglst/express,kylezhang/express,michaeljunlove/express,nodejs-camp/booklog-ausir,weilixia/express,evanlucas/express,codeforgeek/express,igarciaes/express,dsupera13/express,maraoz/express,tjmehta/express,HXYNODE/express,grigorkh/express,BaggersIO/express,xiaofuzi/express,auth0/express,nodejs-camp/booklog-homa,hpcslag/express,swarajgiri/express,thepont/express,evilboss/express,grigorkh/express,gnowoel/express,aifeld/express,1amageek/express,abdulhannanali/express,stewartml/express,kunalpict/express,expressjs/express,juanpastas/express,dgofman/express,featurist/express,1amageek/express,strongloop/express,fuse-mars/express,maraoz/express,jenalgit/express,jinghuizhai/express,RickyDan/express,LestaD/express,leiqiang75/express,kawanet/express,stevemao/express,gnowoel/express,ifraixedes/express,BaggersIO/express,dgofman/express,r14r-work/fork_express_master,Ju2ender/express,nathan818fr/express,flomotlik/express,YR/express,jymsy/express,llwanghong/express,stoskov/express,vidyar/express,elkingtonmcb/express,wtony/express,Lexine/express,wtony/express,abdulhannanali/express,WebStyle/express,buildsample/express,btleffler/express,nodejs-camp/booklog-linkchen,expressjs/express,blakeembrey/express