added APP_MODEL pathname for models unit testing
added APP_MODEL pathname for models unit testing

Signed-off-by: Holloway, Kean Ho <bbd8faa40b0f348214bf4124b281a301299ba6dd@gmail.com>

junster90/shorty,macintorch/bitly-clone,garywong79/w4d5-production_readiness,iamatee/quora_website,NextAcademy/quora-clone,garywong79/w4d2-html-css,garywong79/w4d4-asynchonousform,jylee91/ibilik-accessment,lirenyeo/cut-url-sinatra,garywong79/w4d4-jazzingitupwithJquery,benjaminyeo/sinatra_bnb,jloo87/RR_2_Javascript,anyatan/bitly-clone,hollowaykeanho/sinatra-web-server,dvdhoek/bitly-clone,bsjt10/ibilik-accessment,iamatee/quora_website,garywong79/ibilik,garywong79/w4d1-buildingourfirstwebapp,garywong79/w4d2-html-css,hollowaykeanho/quora-clone-demo,lirenyeo/cut-url-sinatra,anyatan/bitly-clone,alxh87/quora-clone,jylee91/ibilik-accessment,hollowaykeanho/airbnb-accessment,dvdhoek/quora-clone,NaMusS/mini_quora,garywong79/w4d1-extendingshorturl,iamatee/quora_website,garywong79/w4d4-asynchonousform,hollowaykeanho/craigslist,TerryQu3k/BitlyClone,lirenyeo/cut-url-sinatra,bsjt10/ibilik-accessment,garywong79/ibilik,anyatan/bitly-clone,benjaminyeo/sinatra_bnb,dvdhoek/quora-clone,garywong79/w4d4-jazzingitupwithJquery,macintorch/bitly-clone,dvdhoek/bitly-clone,hollowaykeanho/sinatra-web-server,garywong79/w4d5-production_readiness,junster90/shorty,macintorch/bitly-clone,hollowaykeanho/airbnb-accessment,hollowaykeanho/craigslist,yowchun93/Sinatra_flashcards_v2,TerryQu3k/BitlyClone,garywong79/w4d1-buildingourfirstwebapp,syahmiibrahim/sinatra-web-server,WilliamYap3/sinatra-craigslist,dvdhoek/quora-clone,garywong79/w4d1-extendingshorturl,alxh87/quora-clone,NaMusS/mini_quora,hollowaykeanho/ibilik-accessment,hollowaykeanho/quora-clone-demo,ianng89/quora-clone,alxh87/quora-clone,hollowaykeanho/ibilik-accessment,ianng89/quora-clone,syahmiibrahim/sinatra-web-server,junster90/shorty,benjaminyeo/sinatra-craiglist,hollowaykeanho/craigslist,jloo87/RR_2_Javascript,garywong79/mudah.my,garywong79/mudah.my,jylee91/ibilik-accessment,NextAcademy/quora-clone,dvdhoek/bitly-clone,yowchun93/Sinatra_flashcards_v2,ianng89/quora-clone,benjaminyeo/sinatra-craiglist,WilliamYap3/sinatra-craigslist