class Group2(models.Model):
    id_group_vk = models.IntegerField(null=True, blank=True)
    name = models.CharField(max_length=255, null=True, blank=True,)
    screen_name = models.CharField(max_length=255, null=True, blank=True,)
    url_foto_group_vk_50 = models.URLField(verbose_name="ссылка на фото 50", null=True, blank=True)
    url_foto_group_vk_100 = models.URLField(verbose_name="ссылка на фото 100", null=True, blank=True)
    is_closed_group = models.IntegerField(null=True, blank=True,)

    def __int__(self):
        return self.id_group_vk

class Albums(models.Model):
     id_groups_link = models.ForeignKey(Group2,default='',related_name='relate_name_group2_from_Albums')
     id_albums = models.IntegerField(null=True, blank=True)
     id_thumb = models.IntegerField(null=True, blank=True)
     title = models.CharField(max_length=2550, null=True, blank=True)
     description = models.TextField(null=True, blank=True)
     size = models.IntegerField(null=True, blank=True)
     can_upload = models.IntegerField(null=True, blank=True)

class AdminAlbums(admin.ModelAdmin):
    list_display = ('id','id_groups_link','id_albums','id_thumb','title','size','can_upload')

class Group2(models.Model):
id_group_vk = models.IntegerField(null=True, blank=True)
name = models.CharField(max_length=255, null=True, blank=True,)
screen_name = models.CharField(max_length=255, null=True, blank=True,)
url_foto_group_vk_50 = models.URLField(verbose_name="ссылка на фото 50", null=True, blank=True)
url_foto_group_vk_100 = models.URLField(verbose_name="ссылка на фото 100", null=True, blank=True)
is_closed_group = models.IntegerField(null=True, blank=True,)

def __int__(self):
    return self.id_group_vk

def __str__(self):
    return '%s' % (self.id_group_vk)

class Group2(models.Model):
    id_group_vk = models.IntegerField(null=True, blank=True)
    name = models.CharField(max_length=255, null=True, blank=True,)
    ....

    def __str__(self):
        return '{0} - {1}'.format(self.id_group_vk, self.name)