修改 Group 和 Topic model

修改 Group 和 Topic model
完成国家-州省-市县的三级联动
Merge pull request #3 from amituofo/master

修改 Group 和 Topic model  merge
Merge branch 'master' into branch1
完成个人资料的修改功能
Merge branch 'master' of https://github.com/mutoulbj/BOHOO
+group form,copy 'avatar' to 'group_avatar'
完成新建群组
修复用户信息不能修改(忘记添加required=False)
Merge branch 'branch1'
update
User/templates/people/edit.html
	groups/forms.py
	groups/migrations/0001_initial.py
	groups/models.py
	groups/templates/groups/my.html
	groups/todo.js
	groups/views.py