return this.http.post('http://151.80.40.137:1199/login',
  JSON.stringify({ user_login: username, user_password: password }))
        .map((response: Response) =>
        {
            // login successful if there's a jwt token in the response
            let token = response.json() && response.json().jwt.token;
            if (token) {
                // set token property
                this.token = token;

                // store username and jwt token in local storage to keep user logged in between page refreshes
                localStorage.setItem('currentUser', JSON.stringify({ username: username, token: token }));

                // return true to indicate successful login

                this.router.navigate(this.redirectUrl ? [this.redirectUrl] : ['/home']);
                return true;

            } else {
                // return false to indicate failed login

                return  false;
            }
        })
        .catch(err => {
         if (err.status === 401) {
             return "Unauthorized";
           }
           if (err.status === 404) {
               return "Service not working";

      });}