Add test for code change introduced in this commit f20032fa

Provide a call stack for deprecation warnings where needed.

It's sometimes hard to quickly find where deprecated call was performed, especially in case of migrating between Rails versions. So this is an attempt to improve the call stack part of the warning message by providing caller explicitly.

Should not eager_load app/assets
Conflicts:
	railties/CHANGELOG.md

Atomic.rb assumes it may chown/chmod a file but doesn't handle the EPERM error.

Previously this code just assumed it is capable of changing the file
ownership, both user and group. This will fail in a lot of scenario's
unless:
* The process is run as a superuser (root);
* The owning user and group are already set to the user and group we're
  trying to chown to;
* The user chown'ing only changes the group to another group it is a
  member of.
If either of those conditions are not met the filesystem will simply
deny the operation throwing an error.

It is also not always possible to do a chmod, there might be a SELinux
policy or another limitation preventing the user to change the file
mode. To this end the chmod call has also been added to the rescue
block.

I've also added a little comment above the chmod command that doing a
chmod on a file which has an ACL set will cause the ACL to be
recalculated / modified.

Checking for the constant doesn't work

SQLite3Adapter#type_cast should not mutate arguments

Added ActiveRecord::Relation#none! method

Unbreak update_column/update_columns for the primary key attribute.

Didn't work before because it updated the model-in-memory first, so the DB query couldn't find the record.

Replace flow-control exception with explicit test.

Do not render views when mail() isn't called. (NullMail refactoring)

Removing JSON for other ruby

create_table raises an ArgumentError when the primary key is redefined.

AR::AttributeMethods#[] raises AM::AttributeMissingError for missing attributes

This fixes the following behaviour:

    class Person < ActiveRecord::Base
      belongs_to :company
    end

    # Before:
    person = Person.select('id').first
    person[:name]       # => nil
    person.name         # => ActiveModel::MissingAttributeError: missing_attribute: name
    person[:company_id] # => nil
    person.company      # => nil

    # After:
    person = Person.select('id').first
    person[:name]       # => ActiveModel::MissingAttributeError: missing_attribute: name
    person.name         # => ActiveModel::MissingAttributeError: missing_attribute: name
    person[:company_id] # => ActiveModel::MissingAttributeError: missing_attribute: company_id
    person.company      # => ActiveModel::MissingAttributeError: missing_attribute: company_id

Fixes #5433.

Don't log on pending migration check 

Conversation from: #6665 cc/ @rafaelfranca

fix typo in button_to helper example [ci skip]

It was noticed while profiling 'assets:precompile' in JRuby that
exception creation was consuming a large portion of time, and
some of that was due to File.atomic_write.

Testing first with File.exists? eliminates the need for an exception
which should be a perfomrance improvement on both JRuby and MRI.
In this case, the stat() isn't even extra overhead, since it is always
called.

Use the MySQL varbinary type when appropriate in migrations

button_to_function

Point the the Unobtrusive JavaScript secion in the JavaScript guide

Organize README