Remove deprecated Heroku add-on from app.json
Remove deprecated Heroku add-on from app.json

It's now included by default.

orientation/orientation,cmckni3/orientation,robomc/orientation,robomc/orientation,liufffan/orientation,smashingboxes/orientation,LogicalBricks/orientation,jefmathiot/orientation,twinn/orientation,splicers/orientation,friism/orientation,codio/orientation,smashingboxes/orientation,splicers/orientation,Scripted/orientation,ferdinandrosario/orientation,codeschool/orientation,hashrocket/orientation,LogicalBricks/orientation,orientation/orientation,codeschool/orientation,cmckni3/orientation,codio/orientation,orientation/orientation,friism/orientation,ferdinandrosario/orientation,orientation/orientation,IZEA/orientation,codeschool/orientation,liufffan/orientation,jefmathiot/orientation,splicers/orientation,Scripted/orientation,cmckni3/orientation,IZEA/orientation,hashrocket/orientation,Scripted/orientation,twinn/orientation