Update to Rails 5

[mattlindsey]

Update to latest Rails5, currently 5.1.2: http://weblog.rubyonrails.org/2017/6/26/Rails-5-1-2-has-been-released/.

[mattlindsey]

Tried updating Gemfile, running 'bundle update rails' then 'bundle update', but it seems perhaps many gems aren't updated for 5.1.2, or have wrong version numbers:

Bundler could not find compatible versions for gem "railties":
  In Gemfile:
    mercury-rails was resolved to 0.9.0, which depends on
      coffee-rails (>= 3.2.2) was resolved to 4.2.2, which depends on
        railties (>= 4.0.0)

    cucumber-rails was resolved to 1.5.0, which depends on
      railties (< 5.2, >= 4)

    devise was resolved to 4.3.0, which depends on
      railties (< 5.2, >= 4.1.0)

    factory_girl_rails (= 4.5.0) was resolved to 4.5.0, which depends on
      railties (>= 3.0.0)

    factory_girl_rails (= 4.5.0) was resolved to 4.5.0, which depends on
      railties (>= 3.0.0)

    jquery-rails was resolved to 4.3.1, which depends on
      railties (>= 4.2.0)

    jquery-turbolinks (= 2.0.2) was resolved to 2.0.2, which depends on
      railties (>= 3.1.0)

    jvectormap-rails (= 1.0.1) was resolved to 1.0.1, which depends on
      railties (< 5.0, >= 3.1)

    mercury-rails was resolved to 0.9.0, which depends on
      railties (>= 3.0)

    mercury-rails was resolved to 0.9.0, which depends on
      railties (>= 3.0)

    rails (= 5.1.2) was resolved to 5.1.2, which depends on
      railties (= 5.1.2)

    sass-rails was resolved to 5.0.6, which depends on
      railties (< 6, >= 4.0.0)

[mattlindsey]

Getting a little better by replacing jqvmap-rails gem with jvectormap-rails gem:

Bundler could not find compatible versions for gem "activemodel":
  In Gemfile:
    active_model-errors_details was resolved to 1.0.0, which depends on
      activemodel (< 5.0.0.alpha, >= 4.0)

    rails (= 5.1.2) was resolved to 5.1.2, which depends on
      activemodel (= 5.1.2)

    rails (= 5.1.2) was resolved to 5.1.2, which depends on
      activemodel (= 5.1.2)

    rspec-activemodel-mocks was resolved to 1.0.3, which depends on
      activemodel (>= 3.0)

[mattlindsey]

Bundle install now working by removing mercury and active_model-errors_details gems.
So i think now we can proceed to looking at where the tests are failing and try to fix.

[mattlindsey]

Opened issue for 1st error seen when running the site:
activerecord-hackery/polyamorous#23

Looks like polyamorous gem needs some updating for a deprecated method.
If no reply soon, I will try to fix myself and submit PR.