MigrationProxy is used to defer loading of the actual migration classes until they are needed

Methods
B
N
Class Public methods
new(name, version, filename, scope)
     # File activerecord/lib/active_record/migration.rb, line 519
519:     def initialize(name, version, filename, scope)
520:       super
521:       @migration = nil
522:     end
Instance Public methods
basename()
     # File activerecord/lib/active_record/migration.rb, line 524
524:     def basename
525:       File.basename(filename)
526:     end