Fixing /events/{eventId}/users

[harshjohar]

Get all the users concerned with the given event.

Response Object

{
    "participants":[
        {
            "id": userId,
            "email": userEmail,
            "name": userName,
            "photoUrl": userDp
        }
    ],
    "contributors":[
        {
            "id": userId,
            "email": userEmail,
            "name": userName,
            "photoUrl": userDp
        }
    ],
    "publicity":[
        {
            "id": userId,
            "email": userEmail,
            "name": userName,
            "photoUrl": userDp
        }
    ],
}