There are multiple ways of running migrations from the console. This might be the easiest one to remember:
irb ActiveRecord::Schema add_index :followers, [:leader_id, :follower_id], :unique => true
You can also paste the migration code into the console window:
class ModifyRating < ActiveRecord::Migration def self.up change_column :products, :rating, :decimal, :precision => 5, :scale => 3 end def self.down end end
Run the migration by typing ModifyRating.up.