codeclimate/codeclimate-rubocop

This cop checks the migration for which timestamps are not included
when creating a new table.
In many cases, timestamps are useful information and should be added.

### Example:
    # bad
    create_table :users

    # bad
    create_table :users do |t|
      t.string :name
      t.string :email
    end

    # good
    create_table :users do |t|
      t.string :name
      t.string :email

      t.timestamps
    end

    # good
    create_table :users do |t|
      t.string :name
      t.string :email

      t.datetime :created_at, default: -> { 'CURRENT_TIMESTAMP' }
    end

    # good
    create_table :users do |t|
      t.string :name
      t.string :email

      t.datetime :updated_at, default: -> { 'CURRENT_TIMESTAMP' }
    end