public Task <int> AddAsync <T>(T addObj) where T : class
 {
     try
     {
         context.Set <T>().Add(addObj);
         return(context.SaveChangesAsync());
     }
     catch (Exception ex)
     {
         throw ex;
     }
 }
 public async Task <int> Save()
 {
     return(await context.SaveChangesAsync());
 }