Rails 4 - how to use sqlite3 in development and PostgreSQL in production w/Heroku
Don't do it. You are just going to run into problems down the road. Use the same database in production and development. There are a lot of resources available in documenting the switch from a sqlite to postgres database.
Take the time and switch.
Have a look at this Rails Cast.
http://railscasts.com/episodes/342-migrating-to-postgresql?view=asciicast
Try using this for your production DB
production: adapter: postgresql host: localhost encoding: unicode database: my_production_database pool: 5 username: password:You can leave username and password blank