Thanks @egilburg

[ci skip]

[ci skip]

grammar fix in upgrade documentation

Use latest mysql2.

Fixes #11457

Fixed README link in API

Improve ActiveRecord::QueryMethods#includes docs [ci skip]

It's not immediately clear whether you can pass in multiple relations or
not. After going through the code a bit, I saw that the arguments are
just appended to an array. Also, added nested relations example.

[ci skip]

fixes plugin test for tutorial [ci skip]

[ci skip]

Update bcrypt-ruby stable version to 3.1

Only build the missing_keys array once we have detected that there
actually are missing keys by moving the check to be part of the block
that performs the path substitution.

This should not be a link because
it's creating a link with activesupport README right now

When optimized path helpers were re-introduced in d7014bc7 the test added
in a328f2ff broke but no-one noticed because it wasn't being run by the
test suite.

Fix the test by checking for nil values or empty strings after the args
have been parameterized.

This reverts commit cb1d07e4, reversing
changes made to 754a373e.

When generating an unnamed url (i.e. using `url_for` with an options
hash) we should skip anything other than standard Rails routes otherwise
it will match the first mounted application or redirect and generate a
url with query parameters rather than raising an error if the options
hash doesn't match any defined routes.

Fixes #8018

Fixed USAGE file for generator [ci skip]

Move initializing process for @query_cache to QueryCache module.

Fixes AR mysql2 adapter incorrectly casting boolean values

Using the mysql2 adapter, boolean values were sometimes being incorrectly cast
to 't' or 'f'. This changes the cast to match the mysql adapter behavior, ie 1 and 0.

Added generated unit test for generator generator.

Added generated unit test for generator generator and new test:generators rake task included in test:all rake task.