Umbraco V5.1 Relate Member to Node with Relation - MVC Controller

gistfile1.cs

using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using Umbraco.Framework;
using Umbraco.Cms.Web;
using Umbraco.Cms.Web.Context;
using Umbraco.Framework.Persistence.Model.Associations;
using Umbraco.Hive;
using Umbraco.Hive.RepositoryTypes;


namespace TestSite.V5.Web.Controllers
{
    using Umbraco.Framework.Security.Model.Entities;
    using System.Web.SessionState;

    public class MyController : Controller
    {
        private readonly IUmbracoApplicationContext context;

        public MyController(IUmbracoApplicationContext context)
        {
            this.context = context;
        }

        [HttpPost]
        [Authorize()]
        public JsonResult RelateMemberToNode(HiveId nodeID, HiveId memberID, string someValue)
        {
            //Get the member from the member ID
            Member memberToRelate = context.Security.Members.GetById(memberID);

            //Relation Type
            var myRelationType = new RelationType("myRelationTypeAlias");

            //flag for JSON
            bool hasUpdated = false;

            //Open a hive writer - so we can create the relation
            using (var uow = context.Hive.OpenWriter<ISecurityStore>())
            {
                //Try and see if the relation already exists
                var rel = uow.Repositories.GetChildRelations(memberToRelate.ProfileId, myRelationType).SingleOrDefault(x => x.DestinationId.Value == nodeID.Value);

                //Some additional meta data we want to store with the relation
                RelationMetaDatum someMeta = new RelationMetaDatum("someMeta", someValue);

                //Check relation already exists - update the meta value
                if (rel != null)
                {
                    //Update the meta value on the relation
                    uow.Repositories.ChangeOrCreateRelationMetadata(memberToRelate.ProfileId, nodeID, myRelationType, someMeta);

                    //Update flag
                    hasUpdated = true;
                }
                else
                {
                    //The relation does NOT exist - create it
                    //Add meta data to the existing relation

                    //Add a relation (Relate the node to the member)
                    uow.Repositories.AddRelation(memberToRelate.ProfileId, nodeID, myRelationType, someMeta);

                    //Update flag
                    hasUpdated = true;
                }

                //Say we are finished with the UOW/writer
                uow.Complete();
            }

            //Return JSON - with a success message
            return Json(new { updated = hasUpdated });
        }
    }
}