Heroku: How to push seeds.rb to existing rails app?

If you push the app to heroku, you can seed the database with the following command.

heroku run rake db:seed

If you have changed migrations then first you need to do is run migration

heroku run rake db:migrate

then

heroku run rake db:seed

If you don't have any data in database the I would suggest following is, But caution it will remove all current data from heroku database.

heroku run rake db:setup

Hope this helps you