/// <summary>
 /// Add Entity of type T to the database.
 /// </summary>
 /// <param name="entity"></param>
 /// <returns></returns>
 public async Task AddAsync(T entity)
 {
     try
     {
         _context.Set <T>().Add(entity);
         await _context.SaveChangesAsync();
     }
     catch (Exception)
     {
         throw;
     }
 }