增加了加入小组的功能

group/models.py

@@ -11,7 +11,7 @@ class Group(models.Model):
     admin = models.ForeignKey(User, related_name="my_groups")
     # 0是公开 1是需要申请后加入 2是不允许任何人加入
     join_group_setting = models.IntegerField()
-    members = models.ManyToManyField(User)
+    members = models.ManyToManyField(User, through="UserGroupRelation")
     # 解散小组后，这一项改为False
     visible = models.BooleanField(default=True)
 
@@ -19,6 +19,15 @@ class Group(models.Model):
         db_table = "group"
 
 
+class UserGroupRelation(models.Model):
+    group = models.ForeignKey(Group)
+    user = models.ForeignKey(User)
+    join_time = models.DateTimeField(auto_now_add=True)
+    
+    class Meta:
+        db_table = "user_group_relation"
+        
+
 class JoinGroupRequest(models.Model):
     group = models.ForeignKey(User)
     user = models.ForeignKey(User, related_name="my_join_group_requests")