107 api tags user

Closes #107 
Go to the APIs to check and see if the they work.

The urls are the following:
```
http://localhost:8000/api/get/tag/<tag_id>/
http://localhost:8000/api/list/tags_user/<user_id>/
http://localhost:8000/api/list/tags_weightexercise/<weight_id>/
http://localhost:8000/api/list/tags_aerobicexercise/<aerobic_id>/
```
You should be able to view and add to Daniel's user which is user_id 2.