Mention Content-Type for JSON params parsing.

http://stackoverflow.com/questions/8501021/rails-json-request-is-not-parsed-correctly-into-post-parameters
test-case => failing
Fix shorthand routes where controller and action are in the scope

Merge `:action` from routing scope and assign endpoint if both `:controller`
and `:action` are present. The endpoint assignment only occurs if there is
no `:to` present in the options hash so should only affect routes using the
shorthand syntax (i.e. endpoint is inferred from the the path).

Fixes #9856
Clarify what arguments are passed to redirect blocks - fixes #11056
remove trailing whitespace from Active Record CHANGELOG
Fixing  Issue #11083

Removing other occurrences of `the` appearing twice
Merge pull request #11084 from arkiver/master

Fixing issue  #11083
Making the rake file for tests easier to read.

I'm defining a new class which modularizes how the `rake test` tasks are
defined and invoked.
fix deprecation warning in scaffold controllers
Merge pull request #11088 from nolman/nolman/scaffold-fix

fix deprecation warning in scaffold controllers
Change reference to all to scoped instead.

In #11088, `#to_a` was added to remove a deprecation around using
`#all`. I merged, but it really should have been `#scoped` instead, as
that's the preferred replacement.
restore correct scaffold generation
Merge pull request #11093 from nolman/restoring-scaffold-generation

restore correct scaffold generation
We are now rails 4 [skip-ci]
removed unnecessary mapping for on options

Right before that in `assert_valid_transaction_action` method we make
sure that `options[:on]` contains values from `ACTIONS` array
(`[:create, :destroy, :update]`) and nothing more (i.e. it could not
contain strings or something else, otherwise the error is raised).

Also I've polished some docs.
Comment typo
Fixed menu section's location (guides)
Merge pull request #11097 from ryancw/patch-2

ActionView flows comment typo
Merge pull request #11098 from vredniy/master

Fixed menu section's location (guides)
Improve the testing guide [ci skip]

Improve the "Testing Rails Applications" guide adding a section for
testing helpers and a little note about associations with ActiveRecord
and YAML fixtures.

Also add a link to Fixture Builder ; yet another replacement for
fixtures such as Machinist or FactoryGirl.