Fix ActiveRecord `subclass_from_attrs` when eager_load is false.

Conflicts:
	activerecord/CHANGELOG.md

Refactored test case with standard variable names

I've also added a proper acceptance test which reproduced the issue.

Closes #9513, #9515.

Use the index name explicitly provided in a migration when reverting.

Fixes #8868

Conflicts:
	activerecord/CHANGELOG.md

Unprepared Visitor + unprepared_statement

Conflicts:
	activerecord/CHANGELOG.md

Using latest AR-JDBC for JRuby

Introduced in f1082b85.
Full changelog in 9f007d7f.

[ci skip]

7365 merging scopes for where clauses 

schema_statements uses the column name by default to construct the index name, and then raises an exception if it doesn't exist, even if the name option is specified, which causes #8858.  this commit makes index_name_for_remove fall back to constructing the index name to remove based on the name option.

SQLite3 3.6.8+ supports savepoints

http://www.sqlite.org/lang_savepoint.html
https://github.com/rails/rails/blob/master/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb#L130-L132

Currently Post.active.inactive will result in Post.inactive since
the last where clause wins when scopes are merged.

This pull request will merge all scopes ( barring defaul scope)
using AND.

The default scope will be overridden if another scope acts on the
same where clause.

closes #7365

Allow use of assert_template with the :file option.

test case for `serialize` default values.

cache_key consults updated_on timestamp if present

Conflicts:
	activerecord/CHANGELOG.md

Closes #9110

More helpful error message when instantiating an abstract class

Conflicts:
	activerecord/CHANGELOG.md

`has_secure_password` is not invalid when assigning empty Strings

replace non-breaking spaces with normal spaces [ci skip]

Refactored the code to remove irrelevant lines

It was added because a regression caused by a712e08e

Closes #9255

Change useless tr to gsub

`Connection#structure_dump` is no longer used

Closes #9518.

The rake task used to fail silently and left an empty `structure.sql`.
It's confusing for users to get to the root of the problem.
The warning message tells them where to look.

As of ccc6910c we use `mysqldump` to create the `structure.sql`.
The old `#structure_dump` code is still in AR but never used.

I removed all relevant parts from the code-base.

Transactions can be turned off per Migration

Typo in comment to ActionView::Resolver#find_all

CHANGELOG entry for improved singularizing of singulars.

It cannot find subclass because all classes are loaded automatically
when it needs.