module ActiveSupport::ActionableError::ClassMethods  
        
        Public instance methods
Defines an action that can resolve the error.
class PendingMigrationError < MigrationError
  include ActiveSupport::ActionableError
  action "Run pending migrations" do
    ActiveRecord::Tasks::DatabaseTasks.migrate
  end
end
Source code GitHub
# File activesupport/lib/active_support/actionable_error.rb, line 45
def action(name, &block)
  _actions[name] = block
end