Changes I'd make to Damian's blog post example from http://blog.damianbrady.com.au/2012/07/24/a-generic-repository-and-unit-of-work-implementation-for-entity-framework/

Context.cs

public interface IExampleContext
{
    IDbSet<Customer> Customers { get; set; }
}

public class ExampleContext : DbContext, IExampleContext, IUnitOfWork
{
    public CustomerContext(string nameOrConn) : base(nameOrConn) { }

    IDbSet<Customer> Customers { get; set; }
}

CustomerController.cs

public class CustomerController : Controller
{
    private readonly IUnitOfWork uow;
    private readonly CustomerRepository customerRepository;

    public CustomerController(IUnitOfWork uow, CustomerRepository customerRepository)
    {
        this.uow = uow;
        this.customerRepository = customerRepository;
    }

    public ActionResult Edit(CustomerViewModel model)
    {

        var customer = customerRepository.GetById(model.Id);
        // Validate & map viewmodel to model here
        uow.SaveChanges();
    }
}

GenericRepository.cs

public class GenericRepository<TContext, TEntity> : IGenericRepository<TEntity>
    where TContext : IExampleContext
    where TEntity : class
{
    protected TContext _context;
    /// <summary>
    /// Constructor that takes a context
    /// </summary>
    /// <param name="context">An established data context</param>
    public GenericRepository(TContext context)
    {
        _context = context;
    }

    // INSERT REST OF GENERIC REPOSITORY HERE
}

public class CustomerRepository : GenericRepository<IExampleContext, Customer>
{
    public CustomerRepository(IExampleContext context) : base(context) { }
}

IUnitOfWork.cs

public interface IUnitOfWork : IDisposable
{
    int SaveChanges();
}