public async Task <IActionResult> PutWorkout(int id, Workout workout)
        {
            if (id != workout.Id)
            {
                return(BadRequest());
            }

            _context.Entry(workout).State = EntityState.Modified;

            try
            {
                await _context.SaveChangesAsync();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!WorkoutExists(id))
                {
                    return(NotFound());
                }
                else
                {
                    throw;
                }
            }

            return(NoContent());
        }
        public async Task <int> UpdateAsync <T>(T entity, params Expression <Func <T, object> >[] navigations) where T : Entity
        {
            //This code is from the following URL, with a few minor modifications:
            //https://entityframeworkcore.com/knowledge-base/55088933/update-parent-and-child-collections-on-generic-repository-with-ef-core

            var dbEntity = await _context.FindAsync <T>(entity.Id);

            var dbEntry = _context.Entry(dbEntity);

            dbEntry.CurrentValues.SetValues(entity);

            foreach (var property in navigations)
            {
                var propertyName = property.GetPropertyAccess().Name;
                var dbItemsEntry = dbEntry.Collection(propertyName);
                var accessor     = dbItemsEntry.Metadata.GetCollectionAccessor();

                await dbItemsEntry.LoadAsync();

                var dbItemsMap = ((IEnumerable <Entity>)dbItemsEntry.CurrentValue)
                                 .ToDictionary(e => e.Id);

                var items = (IEnumerable <Entity>)accessor.GetOrCreate(entity, false);

                foreach (var item in items)
                {
                    if (!dbItemsMap.TryGetValue(item.Id, out var oldItem))
                    {
                        accessor.Add(dbEntity, item, false);
                    }
                    else
                    {
                        _context.Entry(oldItem).CurrentValues.SetValues(item);
                        dbItemsMap.Remove(item.Id);
                    }
                }

                foreach (var oldItem in dbItemsMap.Values)
                {
                    accessor.Remove(dbEntity, oldItem);
                }
            }

            return(await _context.SaveChangesAsync());
        }