polyglot/db/migrate/20180829122930_create_chat_room_participations.rb

class CreateChatRoomParticipations < ActiveRecord::Migration[5.2]
  def change
    create_table :chat_room_participations do |t|
      t.references :user, foreign_key: true
      t.references :chat_room, foreign_key: true

      t.timestamps
    end
  end
end