Change all `MiniTest` to `Minitest`

Fix to_param when attribute has multibyte character

/cc @pixeltrix

Assigning nil to a polymorphic belongs_to would nullify its _id field by
not its _type field.

Fixes failing test from c141dfc8.
Regression from 1678e959.

duplication removed(DRY)

Fix typo [ci skip]

change to DateTime.civil_from_format from DateTime.civil_from_fromat in ...

[ci skip]

Ref: https://github.com/seattlerb/minitest/blob/master/History.txt

#none documentation updated [ci skip]

Annotated tags will provide us with Tagger and Time information.

allow video_tag to accept `size` as `Number` for square shaped videos

typo: should be 'DateTime.civil_from_format' and not 'DateTime.civil_from_fromat'

Prettify the removals from Action Controller in 4.1 release notes. [ci skip]

Remove the navigator for now. Its ugly and it promises more than it can deliver. These other views (properties, routes) are not designed to be loaded in isolation

Discuss Action Pack's new CSRF protection from remote script tags and what it means for your app. In short, update your tests if they don't already use the 'xhr :post' style.

CSRF protection from cross-origin <script> tags

Thanks to @homakov for sounding the alarm about JSONP-style data leaking

Create a blacklist to disallow mutator methods to be delegated to Array

Conflicts:
	guides/source/upgrading_ruby_on_rails.md