title: what does abstract:true do in ui-router?
body: <p>Sorry my question may seems duplicate beacuse i'm learning Angular JS with some downloaded template but i dint get anything what i exactly need with my searching. </p>
  
  <p>what does abstract: true means?</p>
  
  <p>the main question is  .otherwise('/app/dashboard');  taking me to  partials/app_dashboard.html  if i had mentioned /dashboard in otherwise it should take me there but why /app/dashboard landing me in partials/app_dashboard.html. does abstract: true have any effect in otherwise?</p>
  
  <p>header div, container div(ui-view) and footer div was placed in app.html</p>
  
  <p>$urlRouterProvider</p>
  
  <pre><code>        .otherwise('/app/dashboard');
      $stateProvider            
          .state('app', {
              abstract: true,
              url: '/app',
              templateUrl: 'partials/app.html'
          })
          .state('app.dashboard', {
              url: '/dashboard',
              templateUrl: 'partials/app_dashboard.html'
          })
          .state('app.ui', {
              url: '/ui',
              template: '&lt;div ui-view class="fade-in-up"&gt;&lt;/div&gt;'
          })
  </code></pre>