API does not allow following/unfollowing users or shakes

[spaceninja]

There is no mechanism provided in the API to follow or unfollow a user or a shake.

[spaceninja]

Suggestion: Add the following endpoint (Since you can't follow a user, only the user's shake, this can be solved with one endpoint):

`POST /api/shake_id/(int: shakeid)/follow

(this should also be available on the /api/shake_name and /api/shake_user endpoints.)

Follows the given shake as the authorized user. The contents of this shake will then be included in the user's Friends shake.

Parameters

• shakeid – the shake’s numeric ID

Status Codes

• 200 OK – the shake was followed, and the response is the followed shake
  • If the shake was already followed, then it should be unfollowed. (Question: what should be returned if a shake is unfollowed?)
• 400 Bad Request – the shake could not be followed
• 403 Forbidden – the shake could not be followed due to permission issues
• 404 Not Found – no such shake