In Laravel 5, there is a .env file,
It looks like
APP_ENV=local
APP_DEBUG=true
APP_KEY=YOUR_API_KEY
DB_HOST=YOUR_HOST
DB_DATABASE=YOUR_DATABASE
DB_USERNAME=YOUR_USERNAME
DB_PASSWORD=YOUR_PASSWORD
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
Edit that .env There is .env.sample is there , try to create from that if no such .env file found.