Refactor home page filtering in pages_controller

I tested here and work as expected this feature: http://gembundler.herokuapp.com/v1.2/whats_new.html#local-git-repos

```
   bundle config local.comfortable_mexican_sofa /your-path/to/comfortable-mexican-sofa/
```

Then edit the Gemfile:

```ruby
   gem 'comfortable_mexican_sofa', github: 'moneyadviceservice/comfortable-mexican-sofa', branch: 'master'
```

What do you guys think of it?