change

# File actionmailbox/db/migrate/20180917164000_create_action_mailbox_tables.rb, line 2
  def change
    create_table :action_mailbox_inbound_emails do |t|
      t.integer :status, default: 0, null: false
      t.string  :message_id, null: false
      t.string  :message_checksum, null: false

      t.timestamps

      t.index [ :message_id, :message_checksum ], name: "index_action_mailbox_inbound_emails_uniqueness", unique: true
    end
  end