/// <summary>
        /// Create a StaffCohortAssociation object
        /// </summary>
        /// <param name="cs">the service to use for this action</param>
        /// <param name="associations">the StaffCohortAssociation to create</param>
        /// <returns>result of this action</returns>
        public static async Task<ActionResponseResult> CreateOneStaffCohortAssociation(CohortService cs, string cId, string sId)
        {
            var a = new StaffCohortAssociation { cohortId = cId, staffId = sId, beginDate = DateTime.Now };
            var result = await cs.CreateStaffCohortAssociation(a);

            return GlobalHelper.GetActionResponseResult(sId, "", result, HttpStatusCode.Created);            
        }