Deploying Laravel 5 application on Heroku

I just deployed my laravel 5 app on heroku, but when I try to access it on

http://ift.tt/1ixjlG0

it shows me this error Whoops, looks like something went wrong. error.

This is my .env file

APP_ENV=local
APP_DEBUG=true
APP_KEY=random_string

DB_HOST=localhost
DB_DATABASE=benchmarks
DB_USERNAME=root
DB_PASSWORD=something

CACHE_DRIVER=file
SESSION_DRIVER=file
QUEUE_DRIVER=sync

MAIL_DRIVER=smtp
MAIL_HOST=mailtrap.io
MAIL_PORT=2525
MAIL_USERNAME=null
MAIL_PASSWORD=null
MAIL_ENCRYPTION=null

what should I do to, for my app to show proper error message?

via Chebli Mohamed