I do understand that can be considered as off-topic, but anyway...

This is a command pattern written for django 1.4

It can be used the following way:

    p = DesignPattern()
    imps = Implementation.objects.filter(project='Example')
    DesignPatterImplementationsM2MBind(p, imps) 

Django application models.py file:

    class AbstractM2MBindCommand(AbstractCommand):
        """
        Realizes behaviour design pattern `Command'
        """
        model = None
        model_m2m_field = None
    
        MAX_COMMA_SEPARATED_LENGTH = 1024
    
        bound_objects = models.CommaSeparatedIntegerField(max_length=MAX_COMMA_SEPARATED_LENGTH, null=True, blank=True, default=None)
        bound_objects_long = models.TextField(null=True, blank=True, default=None)
    
        class Meta:
            abstract = True
    
        @classmethod
        def do(cls, model_instance, queryset_to_link):
            #assert isinstance(queryset_to_link, QuerySet)
            setattr(model_instance, cls.model_m2m_field, queryset_to_link)
    
            ids =  [u'%d' % item.pk for item in queryset_to_link]
    
            model_instance.save()
    
            fk_field = camel_to_underscore_convert(cls.model.__name__)
    
            cmd = cls()
            cmd.direction = cls.FORWARD
            joined_ids = u','.join(ids)
            if len(joined_ids) > cls.MAX_COMMA_SEPARATED_LENGTH:
                cmd.bound_objects_long = joined_ids
                cmd.bound_objects = None
            else:
                cmd.bound_objects_long = None
                cmd.bound_objects = u','.join(ids)
            setattr(cmd, fk_field, model_instance)
            cmd.save()


        @classmethod
        def undo(cls, command_id):
            pass

         @classmethod
         def redo(cls, command_id):
             pass 


    class DesignPatterImplementationsBindCommand(AbstractM2MBindCommand):
        model = DesignPattern
        model_m2m_field = 'implementations'
    
        design_pattern = models.ForeignKey(DesignPattern)