change column in rails

 class FixColumnName < ActiveRecord::Migration

  def self.up
    rename_column :table_name, :old_column, :new_column
  end

  def self.down
    # rename back if you need or do something else or do nothing
  end
end

https://dev.to/neshaz/multiple-ways-to-change-database-column-in-rails-34m0