camel->snake on Museum

So many places...

When this is merged, we'll also need to run the following on the production server:
```ruby
 Museum.all.rename(subwayLines: :subway_lines, busLines: :bus_lines, siteUrl: :site_url, 
                   imageUrl: :image_url, handicapAccessible: :handicap_accessible,
                   handsOnActivity: :hands_on_activity, freeAdmission: :free_admission,
                   suggestedDonation: :suggested_donation, phoneNumber: :phone_number,
                   handsOnActivity: :hands_on_activity)
```