Add content to drupalgap drop down
This is the Main Menu section as I see.

You need to made changes "settings.js" file present inside mobile-application\app folder.

Example:

// Main Menu
drupalgap.settings.menus['main_menu'] = {
  options: menu_popup_get_default_options(),
  links: [
    /*
    {
      title:'Content',
      path:'node',
      options:{
        attributes: {
          'data-icon': 'star',
          'class': 'ui-btn ui-btn-icon-right'
        }
      }
    },
    {
      title:'Taxonomy',
      path:'taxonomy/vocabularies',
      options:{
        attributes:{
          'data-icon':'grid'
        }
      }
    },
    {
      title:'Users',
      path:'user-listing',
      options:{
        attributes:{
          'data-icon':'info'
        }
      }
    }
    */
    {
      title:'Home',
      path:'home',
      options:{
        attributes: {
          'data-icon': 'home',
          'class': 'ui-btn ui-btn-icon-right'
        }
      }
    },
    {
      title:'Services',
      path:'websolution',
      options:{
        attributes:{
          'data-icon':'star'
        }
      }
    },
    {
      title:'Our Work',
      path:'ourwork',
      options:{
        attributes:{
          'data-icon':'star'
        }
      }
    },
    {
      title:'About Us',
      path:'articles',
      options:{
        attributes:{
          'data-icon':'star'
        }
      }
    },
    {
      title:'Testimonials',
      path:'testimonial',
      options:{
        attributes:{
          'data-icon':'star'
        }
      }
    },
    {
      title:'Contact',
      path:'node/58',
      options:{
        attributes:{
          'data-icon':'action'
        }
      }
    }

  ]
};


You will get details http://docs.drupalgap.org/7/Menus