[HttpPost]
public ActionResult Login(Login user)
{
    if (ModelState.IsValid)
    {
        if (user.IsValid( user.USERNAME,user.PASSWORD))
        {
            FormsAuthentication.SetAuthCookie(user.USERNAME, false);
            // I WANT TO ADD ROLES HERE FOR THE USER
            return RedirectToAction("Index", "Home");
        }
        else
        {
            ModelState.AddModelError("", "Login data is incorrect!");
        }
    }
    return View(user);
}

[AuthorizeUser(Roles = "MasterAdmin")]
[OutputCache(Duration = 0, NoStore = true)]
public class MasterCompaniesController : Controller
{
    private DEMTContext db = new DEMTContext();

    // GET: MasterCompanies
    public ActionResult Index()
    {
        return View(db.MasterCompanys.ToList());
    }
}

public class AuthorizeUserAttribute:AuthorizeAttribute
    {
        //private readonly string[] allowedroles;


        protected override bool AuthorizeCore(HttpContextBase httpContext)
        {


            bool IsThisMasterAdmin = false;

            using(DEMTContext db = new DEMTContext())
            {
                string username= httpContext.User.Identity.Name;

                var map = db.MasterAdminPasswords.Where(m => m.MASTERADMINPASSWORD == username).FirstOrDefault();//FOR SIMPLIFICATION, PASSWORD IS OMITTED FOR VERIFICATION
                if (map != null && Roles.Contains("MasterAdmin"))
                {
                    IsThisMasterAdmin = true;
                    GenericIdentity gi = new GenericIdentity(passcode);
                    GenericPrincipal gp = new GenericPrincipal(gi, new string[] { "MasterAdmin" });
                    httpContext.User = gp;
                    return IsThisMasterAdmin;
                }
            }
            return false;
        }
    }

@if (User.IsInRole("MasterAdmin"))
                        {
                            if (User.Identity.IsAuthenticated)
                            {
                                <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">Hello <span class="caret"></span></a>
                                <ul class="dropdown-menu">
                                    @*<li><a href="#"><label class="label label-info">COMPANY : @Request.Cookies["COMPANYNAME"].Value</label></a></li>
                                    <li role="separator" class="divider"></li>
                                    <li><a href="#">Profile</a></li>
                                    <li><a href="#">Settings</a></li>
                                    <li role="separator" class="divider"></li>*@
                                    <li><a href="@Url.Action("Logout", "MasterAdmin")">Logout</a></li>
                                </ul>
                            }
                    }