Upgrading rails version

From Rails 3.1 to 3.2

Deprecation warnings while testing locally

Travis logs these warnings (https://travis-ci.org/tansaku/LocalSupport/builds/9474191)

rspec stub! is deprecated

rspec mock is deprecated - use double

Deprecation warnings while deploying to Heroku

https://gist.github.com/mtc2013/6079095

From 3.2 to 4.0

Gmaps blank on first display

(https://github.com/apneadiving/Google-Maps-for-Rails/issues/357)

vendor/plugins

LocalSupport doesn't use vendor plugins but heroku does

Heroku will hopefully deal automatically with the deprecation warnings

(http://stackoverflow.com/a/9042604)

(https://devcenter.heroku.com/articles/rails4#upgrading-a-rails3-app)

Mass assignment protection

protected_attributes gem or strong parameters protection model? (gem not supported after 4.0)

(http://weblog.rubyonrails.org/2012/3/21/strong-parameters/) (http://edgeapi.rubyonrails.org/classes/ActionController/StrongParameters.html)

TurboLinks

(http://guides.rubyonrails.org/working_with_javascript_in_rails.html#turbolinks

HTTP verb constraint

(http://guides.rubyonrails.org/routing.html#http-verb-constraints)