public async Task <IHttpActionResult> CreateConversation(int userID, int friendID)
        {
            if (!ModelState.IsValid)
            {
                return(BadRequest(ModelState));
            }

            var user = await db.Users.FirstOrDefaultAsync((u) => u.UserID == userID);

            if (user == null)
            {
                NotFound();
            }

            var friend = await db.Users.FirstOrDefaultAsync(u => u.UserID == friendID);

            if (friend == null)
            {
                NotFound();
            }

            await Task.Run(() => db.CreateAConversation(userID, friendID));

            var conversationFullInfo = await Task.Run(() =>
                                                      (
                                                          db.Participants
                                                          .Where(u => u.UserID == userID)
                                                          .Where(g => g.Group.GroupType == "CONVERSATION")

                                                          .Intersect(
                                                              db.Participants
                                                              .Where(u => u.UserID == friendID)
                                                              .Where(g => g.Group.GroupType == "CONVERSATION"))
                                                      ).FirstOrDefaultAsync()
                                                      );

            var conversationID = conversationFullInfo.GroupID;

            return(Json <int?>(conversationID));
        }