public ActionResult AddFiles([FromBody] ICollection <Medium> files, int channelId)
        {
            var tokenEntry = _tokenManager.ValidateAndReturnTokenEntry(_tokenManager.ExtractToken(Request));

            if (tokenEntry != null)
            {
                var currEvent = _dbContext.Events.Where(x => x.ChannelId == channelId).FirstOrDefault();
                if (currEvent != null)
                {
                    var rosterEntry = _dbContext.EventRosterEntries.Where(x => x.EventId == currEvent.EventId && x.AttendeeId == tokenEntry.UserId).FirstOrDefault();
                    if (rosterEntry != null && tokenEntry.UserId != currEvent.EventOrganiserId)
                    {
                        _fileManager.AddFilesToChannel(files, channelId, currEvent.EventId, tokenEntry.UserId);
                        return(Ok());
                    }
                    return(BadRequest("User is not registered for event"));
                }
                return(BadRequest("Event is not valid"));
            }
            return(StatusCode(401, SystemResources.INVALID_TOKEN_MESSAGE));
        }