django多对多关联表的操作

class AssetGroup(models.Model):
GROUP_TYPE = (
('P','PRIVATE'),
('A','ASSET')
)
name = models.CharField(max_length=80,unique=True)
comment = models.CharField(max_length=300,blank=True,null=True)

def __unicode__(self):
return self.name

class Asset(models.Model):
"""
定义资产信息
"""
group = models.ManyToManyField(AssetGroup, blank=True, verbose_name=u"项目名")
env = models.IntegerField(choices=ASSET_ENV, blank=True, null=True, verbose_name=u"运行环境")
ip = models.CharField(max_length=32, blank=True, null=True, verbose_name=u"主机IP")
other_ip = models.CharField(max_length=255, blank=True, null=True, verbose_name=u"联通ip或者云主机ip")
system_version = models.CharField(max_length=8, blank=True, null=True, verbose_name=u"系统版本号")
kernel_version = models.CharField(max_length=32,blank=True,null=True,verbose_name=u'内核版本信息')
ssh_version = models.CharField(max_length=32,blank=True,null=True,verbose_name=u'ssh版本信息')
status = models.IntegerField(choices=ASSET_STATUS, blank=True, null=True, default=1, verbose_name=u"机器状态")
idc = models.ForeignKey(IDC, blank=True, null=True,  on_delete=models.SET_NULL, verbose_name=u'机房')
cpu = models.CharField(max_length=64, blank=True, null=True, verbose_name=u'CPU')
memory = models.CharField(max_length=128, blank=True, null=True, verbose_name=u'内存')
disk = models.CharField(max_length=1024, blank=True, null=True, verbose_name=u'硬盘')
date_added = models.DateTimeField(auto_now=True, null=True)
comment = models.CharField(max_length=128, blank=True, null=True, verbose_name=u"备注")

2.具体操作：
当添加了资产和项目的时候，发现这2者并未产生关联，没有对关联表进行任何操作，所以需要对关联表进行操作进行关联
在视图里面的操作如下：

Group = AssetGroup.objects.filter(