Question

how to save data into database when rails migration run. I have records of city and i would like to save data into databases when i create a table.

Answer 1

The db/seeds.rb file is there so you can add seeded data to your database. You can create your records inside of there using ActiveRecord (it is just a ruby file):

City.create! :name => "New York", ...

You can populate your database with your seeds by running rake db:seed. You can also chain your migration/seed commands together:

rake db:migrate db:seed