What is the reference for .Create() method, Entity Framework 6

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MVC4

EF6.0

Dear All.
I am trying to build a User authentication in ASP.Net MVC4 from a tutorial. I am already done with 80 % of the project but at the end i have faced with a problem. I couldn't get a clue even googling for an hour.
I have a user control just like below.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Security;
using System.Data.EntityModel;
using System.Data.Entity;
using System.Data.EntityClient;
using System.Data.OracleClient;
using System.Data.Objects.SqlClient;



namespace SimplyLogInSystem.Controllers
{
    public class UserController : Controller
    {
        private object sysUser;
        //
        // GET: /User/

        public ActionResult Index()
        {
            return View();
        }

        [HttpGet]
        public ActionResult LogIn()
        {
            return View();
        }

        [HttpPost]
        public ActionResult LogIn(Models.UserModel user)
        {
            if (ModelState.IsValid)
            {
                if (IsValid(user.Email, user.Password))
                {
                    FormsAuthentication.SetAuthCookie(user.Email, false);
                    return RedirectToAction("Index", "Home");
                }
                else
                {
                    ModelState.AddModelError("", "Login data is incorrect.");
                }
            }
            return View(user);
        }


        [HttpGet]
        public ActionResult Registration()
        {
            return View();
        }


        [HttpPost]
        public ActionResult Registration(Models.UserModel user)
        {
            if (ModelState.IsValid)
            {
                using (var db = new MainDbContext())
                {
                    var crypto = new SimpleCrypto.PBKDF2();

                    var encrpPass = crypto.Compute(user.Password);

                    var sysUsers = SystemUser.CreateSystemUser(Guid.NewGuid(), user.Email, encrpPass, crypto.Salt);

                    var sysUser = db.SystemUsers.Create();

                    db.SaveChanges();
                    return RedirectToAction ("Index", "Home");
                }
            }
            else
            	{
                    ModelState.AddModelError("", "Registration data is incorrect.");
            	}

            return View();
        }

and i have a model and a view for it.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;

namespace SimplyLogInSystem.Models
{
    public class UserModel
    {
        [Required]
        [StringLength(50)]
        [DataType(DataType.EmailAddress)]
        [Display(Name="Email Address:")]
        public string Email { get; set; }


        [Required]
        [DataType(DataType.Password)]
        [StringLength(20, MinimumLength = 6)]
        [Display(Name = "Password:")]
        public string Password { get; set; }

    }
}

The problem i am facing is that when i want to create the System User it ask for reference of .Create() which i don't have a clue on that. Can you help me with that as I am new to MVC and entity framework?