(1)AngularJS service

$ vi app/assets/javascripts/mymodule.js.erb

myModule.factory("flashService", function ($rootScope) {
  var currentUser = { user: {id: 0} };
  return {
    getUser: function () {
      return currentUser;
    },
    setUser: function (user) {
      currentUser = user;
    }
  };
});

(2)AngularJS controller

$ vi app/assets/javascripts/mymodule.js.erb

myModule.controller("SessionsNewCtrl", function($scope, sessionResource, $location, flashService) {
  $scope.submit = function() {
    function success(response) {
      var user_info = response;
      flashService.setUser(user_info);
      $location.path("/users/" + response.user.id);
    }
    function failure(response) {
........
    }
    sessionResource.create($scope.session, success, failure);
  };

ref.
Rails "sessions" controller

  def create
    user = User.find_by(email: session_params[:email].downcase)
    if user && user.authenticate(session_params[:password])
      remember_token = User.new_remember_token
      cookies.permanent[:remember_token] = remember_token
      user.update_attribute(:remember_token, User.encrypt(remember_token))
      @user_info = {
        user: user
      }
      render json: @user_info, status: :accepted, location: user
    else
      msg = {"password" => ["Invalid email/password combination"]}
      render json: msg, status: :unprocessable_entity
    end
  end

(3)navigation menu

1)AngularJS template view 

$ vi app/views/layouts/_header.html.erb

<div ng-controller="CollapseDemoCtrl" class="navbar navbar-default navbar-fixed-top" role="navigation">
.........
  <div class="navbar-collapse" collapse="isCollapsed">
    <ul class="nav navbar-nav">
.........
      <li ng-hide="chkSignin().user.id > 0"><%= link_to "Sign in", "/signin" %></li>
      <li ng-show="chkSignin().user.id > 0"><%= link_to "Users", "/users" %></li>
      <li ng-show="chkSignin().user.id > 0" class="dropdown" dropdown>
        <a class="dropdown-toggle" dropdown-toggle>Account<span class="caret"></span></a>
        <ul class="dropdown-menu">
          <li><%= link_to "Profile", "/users/{{chkSignin().user.id}}/" %></li>
          <li><%= link_to "Settings", "/users/{{chkSignin().user.id}}/edit" %></li>
          <li role="separator" class="divider"></li>
          <li><%= link_to "Sign out", "/signout" %></li>
        </ul>
      </li>

2)AngularJS controller

$ vi app/assets/javascripts/mymodule.js.erb

function CollapseDemoCtrl($scope, flashService) {
  $scope.chkSignin = function() {
    return flashService.getUser();
  };
}

(4)countermeasure of the browser reload

1)AngularJS run method

myModule.run(function (sessionResource,flashService) {
  sessionResource.current_user({}, function(response) {
    if (response.user && response.user.id) {
      var user_info = response;
    } else {
      var user_info = { user: {id: 0} };
    }
    flashService.setUser(user_info);
  });
});

myModule.factory("sessionResource", function($resource) {
  return $resource("/app/sessions", {},
    {
      'create':  { method: 'POST' },
      'destroy': { method: 'DELETE' },
      'current_user': { method: 'GET', isArray: false }
    }
  );
});

myModule.factory("flashService", function ($rootScope) {
  var currentUser = { user: {id: 0} };
  return {
    getUser: function () {
      return currentUser;
    },
    setUser: function (user) {
      currentUser = user;
    }
  };
});

2)Rails route

$ vi config/routes.rb

  match '/app/sessions', to: 'sessions#current_user', via: 'get'

3)Rails "sessions" controller

$ vi app/controllers/sessions_controller.rb

  def current_user
    remember_token = User.encrypt(cookies[:remember_token])
    current_user ||= User.find_by(remember_token: remember_token)
    @user_info = {
      user: current_user
    }
    render json: @user_info, status: :accepted
  end