Mock server

# Approvals Required:
- [ ] @NahimNasser (Nahim)


# Stories
1. [MOB-1129] As a developer I want to mock out all API endpoints

# Notes
This is a static mock of the API endpoint to unblock any dependancies for front end development purposes. 

# API details: 
[MOB-1120]
- Return the id of the new group of a successful API call to create a Facebook group. 
- Used in wires at: 6.1.1
- POST /groups/create
- Parameters:app-id=int, name=string, description=string, privacy=boolean, admin-id=int


[MOB-1182]
- Invite Facebook friend to group. Returns success or an error. 
- Used in wires at: 6.0, 6.1.1, 6.2 
- POST /groups/invite/<group-id>/members 
- Parameters: member-id=int


[MOB-1029]  
- Returns all the game groups that are associated with the app: 
- Used in wires at: 6.0
- GET /groups                                                                            


[MOB-970] 
- Sets the users TOC to share courses to True or False. Returns success or error. 
- Used in wires at: 8.0
- POST: /share_courses
- Parameters: share_courses=Boolean 


[MOB-904]
- Returns the friends that are edX users that are in the course indicated by course id
- Used in wires at: 3.0, 2.0, 2.2 
- GET: /friends/course/<course-id>                                                        


[MOB-1183]
- Returns all the friends that are edX users that are in the group 
- Used in wires at: 6.0
- GET: /friends/group/<group-id>


[MOB-971]
- Returns all the courses the user has friends in:
- Used in wires at: 3.0
- GET: /friends