Made services orderable

[anna-oake]

Fixes #1 issue.
Also fixed minor .gitignore issue and made service groups appear after single services, since it's much more logical for me.

[nioupola]

Hello,
I apply this PR on my fork but can't see how to get the URL to order the services.
Can you tell me how we use this PR?
Thanks in advance

[nioupola]

I found the fix :

  sortabledata = document.getElementsByClassName('data-orderable-list')[0]
  sortable = new Sortable(sortabledata,
      onUpdate: ->
        orderedIds = $.map($(this.el).find('.data-orderable-id'), (elem) ->
          $(elem).data 'orderable-id'
        )
        $.ajax
          async: true
          url: "/admin/services/reorder"
          type: 'POST'
          data: ids: orderedIds
    )