model定义如下:

class Tag(models.Model):
    id = models.AutoField(primary_key=True)
    name = models.CharField(max_length=100,verbose_name='名称')
    def __unicode__(self):
        return self.name


class Post(models.Model):
    id = models.AutoField(primary_key=True)
    author = models.ForeignKey(User)
    post_date = models.DateField(verbose_name='日期', auto_now=True)
    post_title = models.CharField(verbose_name='标题', max_length=100)
    post_content = RichTextField(verbose_name='内容')
    post_tag = models.ForeignKey(Tag, verbose_name='标签')

在views.py里我是这样写的：

def tag(request, tag):
    post_list = Post.objects.filter(post_tag.name = tag)
    return render_to_response('tag.html',{'post_list':post_list,'tag':tag})

直接报语法错误Unresolved reference ‘post_tag’，如果写成post_tag = tag，网页上会报

ValueError at /tag/test/

invalid literal for int() with base 10: 'test'

Request Method:     GET
Request URL:    http://127.0.0.1:8000/tag/test/
Django Version:     1.7.1
Exception Type:     ValueError
Exception Value:    

invalid literal for int() with base 10: 'test'

就是想筛选下post_tag等于tag的Post，究竟该怎么写？