code: function (appID, locationID) {
  
      // check if location exists
      if (l_locations.hasOwnProperty(locationID) === false) {
          LOG.error('locationID: ' + locationID + ' does not exist', 'addApp');
          return;
      }
  
      // check if already exists, ignore action if already exists
      if (l_apps.hasOwnProperty(appID) === true) {
          LOG.error('appID: ' + appID + ' already exists', 'addApp');
          return;
      }
  
      // insert new app record for this location
      l_apps[appID] = {
          locationID: locationID,
          users: {}
      }
  
      // build mapping from location to app 
      // TODO: (needed? or can simplfiy?)
      l_locations[locationID].apps[appID] = l_apps[appID];    
  }
docs: add a new app