Update "Underscored Keys, `_id` and `_ids`" section
Update "Underscored Keys, `_id` and `_ids`" section

ActiveModelSerializer is finished and works like magic.

Furthermore, the previous code was not enough to make ember data work with underscored attributes (see issue #1428)
sebastianseilund/data,funtusov/data,fpauser/data,jgwhite/data,fpauser/data,vikram7/data,webPapaya/data,topaxi/data,gabriel-letarte/data,offirgolan/data,rtablada/data,heathharrelson/data,sebastianseilund/data,splattne/data,dustinfarris/data,minasmart/data,XrXr/data,thaume/data,splattne/data,danmcclain/data,tstirrat/ember-data,BBLN/data,intuitivepixel/data,EmberSherpa/data,InboxHealth/data,usecanvas/data,slindberg/data,BBLN/data,kappiah/data,bcardarella/data,BookingSync/data,davidpett/data,pdud/data,jmurphyau/data,Robdel12/data,heathharrelson/data,sammcgrail/data,martndemus/data,heathharrelson/data,sebweaver/data,faizaanshamsi/data,BookingSync/data,Kuzirashi/data,Addepar/ember-data,dustinfarris/data,gniquil/data,funtusov/data,sammcgrail/data,topaxi/data,yaymukund/data,sammcgrail/data,sammcgrail/data,simaob/data,XrXr/data,Robdel12/data,rtablada/data,tstirrat/ember-data,XrXr/data,EmberSherpa/data,Turbo87/ember-data,XrXr/data,tstirrat/ember-data,mphasize/data,in4mates/ember-data,k-fish/data,eriktrom/data,H1D/data,intuitivepixel/data,dustinfarris/data,gniquil/data,Turbo87/ember-data,gkaran/data,faizaanshamsi/data,Robdel12/data,trisrael/em-data,davidpett/data,bcardarella/data,pdud/data,arenoir/data,swarmbox/data,vikram7/data,minasmart/data,eriktrom/data,jgwhite/data,zoeesilcock/data,HeroicEric/data,jmurphyau/data,andrejunges/data,tarzan/data,jmurphyau/data,PrecisionNutrition/data,bf4/data,whatthewhat/data,webPapaya/data,simaob/data,faizaanshamsi/data,danmcclain/data,bcardarella/data,danmcclain/data,bf4/data,funtusov/data,k-fish/data,heathharrelson/data,Turbo87/ember-data,arenoir/data,fpauser/data,lostinpatterns/data,in4mates/ember-data,H1D/data,wecc/data,wecc/data,tarzan/data,martndemus/data,Kuzirashi/data,tonywok/data,gabriel-letarte/data,fpauser/data,stefanpenner/data,slindberg/data,dustinfarris/data,kappiah/data,InboxHealth/data,stefanpenner/data,seanpdoyle/data,kimroen/data,HeroicEric/data,andrejunges/data,wecc/data,vikram7/data,duggiefresh/data,thaume/data,fsmanuel/data,jgwhite/data,courajs/data,InboxHealth/data,bcardarella/data,mphasize/data,funtusov/data,gniquil/data,usecanvas/data,workmanw/data,swarmbox/data,greyhwndz/data,Kuzirashi/data,nickiaconis/data,whatthewhat/data,HeroicEric/data,courajs/data,ryanpatrickcook/data,PrecisionNutrition/data,PrecisionNutrition/data,gkaran/data,BBLN/data,eriktrom/data,flowjzh/data,tstirrat/ember-data,pdud/data,ryanpatrickcook/data,swarmbox/data,bf4/data,BBLN/data,ryanpatrickcook/data,yaymukund/data,Turbo87/ember-data,hibariya/data,sebastianseilund/data,Eric-Guo/data,knownasilya/data,davidpett/data,andrejunges/data,offirgolan/data,eriktrom/data,greyhwndz/data,slindberg/data,EmberSherpa/data,FinSync/ember-data,vikram7/data,courajs/data,yaymukund/data,HeroicEric/data,nickiaconis/data,H1D/data,splattne/data,thaume/data,gkaran/data,gabriel-letarte/data,martndemus/data,ryanpatrickcook/data,flowjzh/data,usecanvas/data,gniquil/data,acburdine/data,fsmanuel/data,Kuzirashi/data,tonywok/data,swarmbox/data,tonywok/data,fsmanuel/data,nickiaconis/data,jmurphyau/data,flowjzh/data,whatthewhat/data,tarzan/data,zoeesilcock/data,k-fish/data,thaume/data,kimroen/data,minasmart/data,Eric-Guo/data,FinSync/ember-data,BookingSync/data,offirgolan/data,faizaanshamsi/data,courajs/data,intuitivepixel/data,arenoir/data,greyhwndz/data,seanpdoyle/data,splattne/data,lostinpatterns/data,pdud/data,webPapaya/data,Addepar/ember-data,fsmanuel/data,H1D/data,kimroen/data,zoeesilcock/data,stefanpenner/data,sebweaver/data,lostinpatterns/data,InboxHealth/data,Eric-Guo/data,wecc/data,hibariya/data,yaymukund/data,danmcclain/data,topaxi/data,BookingSync/data,davidpett/data,k-fish/data,duggiefresh/data,gabriel-letarte/data,hibariya/data,workmanw/data,arenoir/data,mphasize/data,PrecisionNutrition/data,sebastianseilund/data,hibariya/data,FinSync/ember-data,tarzan/data,intuitivepixel/data,whatthewhat/data,bf4/data,usecanvas/data,flowjzh/data,jgwhite/data,simaob/data,mphasize/data,lostinpatterns/data,duggiefresh/data,knownasilya/data,tonywok/data,Addepar/ember-data,trisrael/em-data,FinSync/ember-data,EmberSherpa/data,minasmart/data,topaxi/data,sebweaver/data,kappiah/data,trisrael/em-data,gkaran/data,workmanw/data,simaob/data,knownasilya/data,seanpdoyle/data,stefanpenner/data,in4mates/ember-data,rtablada/data,greyhwndz/data,Robdel12/data,nickiaconis/data,Eric-Guo/data,offirgolan/data,webPapaya/data,acburdine/data,seanpdoyle/data,sebweaver/data,kappiah/data,zoeesilcock/data,duggiefresh/data,acburdine/data,rtablada/data,andrejunges/data,martndemus/data,acburdine/data,workmanw/data