Repository.cs

    public class Repository<T> : IQueryable<T> where T : class
    {
        private readonly DbSet<T> _set;

        public Repository(DbSet<T> set)
        {
            _set = set;
        }

        public void Add(T entity)
        {
            _set.Add(entity);
        }

        public void Delete(T entity)
        {
            _set.Remove(entity);
        }

        #region IQueryable<T> implementation

        public IEnumerator<T> GetEnumerator()
        {
            return _set.AsEnumerable().GetEnumerator();
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return this.GetEnumerator();
        }
         
        public Expression Expression
        {
            get { return ((IQueryable<T>) _set).Expression; }
        }

        public Type ElementType
        {
            get { return typeof (T); }
        }

        public IQueryProvider Provider
        {
            get { return ((IQueryable<T>) _set).Provider; }
        }

        #endregion
    }