public IActionResult AttachPermissionToRole(string roleName, string permissionName)
 {
     try
     {
         var role       = _uow.Repository <Role>().Get(r => r.Name == roleName);
         var permission = _uow.Repository <Permission>().Get(per => per.Name == permissionName);
         if (role != null && permission != null)
         {
             var resp = _permissionManager.AttachPermissionToRole(permission, role);
             _uow.Save();
             var respVm = Mapper.Map <PermissionVm>(resp);
             return(Ok(respVm));
         }
         else
         {
             throw new ArgumentException("Invalid Arguments");
         }
     }
     catch (Exception ex)
     {
         return(StatusCode(500, ex.Message));
     }
 }