fetch(req, res, next, id) {
   this.userRepository.findById(id)
     .onFulfill((user) => {
       if(! user) {
         throw new ModelNotFoundError(id);
       }
       req.fetchedUser = user;
       next();
     }).onReject(next);
 }

  private createSuperUser() {
    let superUser: IUser = {
      display_name: "Kareem Mohamed",
      username: "kareem",
      local: {
        email: "[email protected]",
        password: "kareem123",
        fname: "Kareem",
        lname: "Mohamed",
        validated: true
      }
    };

    return this.userRepository.create(superUser);
  }

  authenticateLocal(attributes) {
    // Authenticate local user
    let {email, password} = attributes;

    return this.userRepository.checkLocal(email, password);
  }

 private addAdminRole(user, shop) {
   return this.userRepository.addRoleByUsername(user.username, {
     role: "admin",
     shop_id: shop._id
   });
 }

 .then(user_id => this.userRepository.findById(user_id))

 all(req, res, next) {
   this.userRepository.find(req.query)
     .onFulfill((users) => {
       this.successResponse(res, users);
     }).onReject(next);
 }