Add extra categories/sub-categories

[Pjaerr]

Currently there are the following categories and their sub categories (defined in /frontend/pages/index.js)

{
    name: 'Attractions',
    subCategories: [
      { displayName: 'Museums', query: 'Museums' },
      { displayName: 'Theme Parks', query: 'Theme Parks' },
      { displayName: 'Historic', query: 'Historic' },
      { displayName: 'Art', query: 'Art' },
      { displayName: 'Theatre', query: 'Theatre' },
      { displayName: 'Zoos', query: 'Zoos' }
    ]
  },
  {
    name: 'Sights',
    subCategories: [
      { displayName: 'Landmarks', query: 'Landmarks' },
      { displayName: 'Lakes', query: 'Lakes' },
      { displayName: 'Parks', query: 'Parks' },
      { displayName: 'City Views', query: 'City Views' }
    ]
  },
  {
    name: 'Social',
    subCategories: [
      { displayName: 'Nightlife', query: 'Nightlife' },
      { displayName: 'Pubs', query: 'Pubs' },
      { displayName: 'Sports', query: 'Sports' },
      { displayName: 'Community', query: 'Community' }
    ]
  },
  {
    name: 'Food',
    subCategories: [
      { displayName: 'Chinese', query: 'Chinese Food' },
      { displayName: 'American', query: 'American Food' },
      { displayName: 'German', query: 'German Food' },
      { displayName: 'Spanish', query: 'Spanish Food' },
      { displayName: 'Vietnamese', query: 'Vietnamese Food' },
      { displayName: 'Thai', query: 'Thai Food' },
      { displayName: 'Indian', query: 'Indian Food' },
      { displayName: 'Japanese', query: 'Japanese Food' }
    ]
  }
];

The categories (eg. Attractions, Sights) are searched for when the user selects Everything under the respective category and the Sub categories are given their own box to be selected. On clicking the box, it will just send the text in query to the foursquare api as a search query.

With that in mind, any category or subcategory can be added to this list and it should work as expected, provided every sub category has a corresponding image in /frontend/static/category-images matching the name of its query.