We have three or four different introduction sentences to the guides.
After this commit, we use the same one everywhere.

Talked with @fxn about this. Bullet points should have periods at the ends.

The proper name, as per the documentation guides, is 'Active Record.' I've
updated several references to it as 'ActiveRecord'.

This reverts commit 25648ce3.

The shortcut ampersand syntax of `select.map(&:field)` is same thing as `.plunk(:field)`. document that

This is similar to #first_or_create, but slightly different and a nicer
API. See the CHANGELOG/docs in the commit.

Fixes #7853

This reverts commit f5b9ed4f.

REASON: Translation work can not be done in the docrails repository

You need to have @implicit_readonly set for this to happen,
and it's false by defualt.

Fixes #3386.

In Textile `*` would convert to `<strong>`, but in Markdown we have to
use `**` instead.

Allows you to specify the model association key in a belongs_to
relationship instead of the foreign key.

The following queries are now equivalent:

Post.where(:author_id => Author.first)
Post.where(:author => Author.first)

PriceEstimate.where(:estimate_of_type => 'Treasure', :estimate_of_id => treasure)
PriceEstimate.where(:estimate_of => treasure)

    User.order("name asc").order("created_at desc")
    # SELECT * FROM users ORDER BY created_at desc, name asc

This also affects order defined in `default_scope` or any kind of associations.