Don't require 'turn' from rails/test_help

This avoids "SECURITY WARNING: No secret option provided to Rack::Session::Cookie."

Update guides/source/getting_started.md [ci skip]

    actions.rb:34: warning: instance variable @in_group not initialized

Related to the change introduced in 6cf47c53.

The doc:rails application rake task needs this README.

Closes #8804 [ci skip]

Improve StrongParameters documentation [ci skip]

Place article name in the beginning of guides page title

These warnings were actually a bug in Ruby 2.0, the accessors should not
be raising such warnings, they are only meant for ivars.

-

Revert "fix warnings in Ruby 2.0"

This reverts commit 26702a6d.

-

Revert "Merge pull request #8282 from arunagw/warning_removed_for_ruby2"

This reverts commit f63d6544, reversing
changes made to 3a890681.

Reflect change in 009873ae that renamed the script/ folder to bin/

If 'turn' is in the Gemfile with `:require => nil`, Rails should
respect that.

This supports the case where 'turn' may or may not be required
depending on different developers' preference or environment. E.g., you
require turn for local testing, but not on your CI server by putting
this in `test/test_helper.rb`:

    require 'turn' if ENV['TURN']

Access ivars via instance reader methods for consistency

Refactor ShowExceptions' #call to use def-rescue instead of begin-rescue

Remove begin-rescue in favor of def-rescue

Introduce ./bin for your app's executables: bin/bundle, bin/rails, bin/rake

Introduce ./bin for your app's executables: bin/bundle, bin/rails, bin/rake. Executable scripts are versioned code like the rest of your app. To generate a stub for a bundled gem: 'bundle binstubs unicorn' and 'git add bin/unicorn'

All the valids parameters for libpq are used.

See http://www.postgresql.org/docs/9.1/static/libpq-connect.html for the
full list

Fixes #8784

masgn and response variable

Refactor DebugExceptions

Refactor Journey::Routes