Prevent Numeric#to_s from allocating an array
Allow failures with Active Job
Allow failures with Active Job integration tests
[ci skip] fix class name
Merge pull request #17828 from yui-knk/fix/i18n_guide

[ci skip] fix class name
Remove a reference to Ruby 1.9 in Guides

[ci skip]

Now that Rails requires Ruby >= 2.0 there is no need to document
Ruby 1.9.
Merge pull request #17838 from claudiob/remove-ruby19-reference-in-guides

Remove a reference to Ruby 1.9 in Guides
Bump required Ruby version to 2.1.0

[This article](http://weblog.rubyonrails.org/2014/8/20/Rails-4-2-beta1/#maintenance-consequences-and-rails-5-0) states that:

> Rails 5.0 is in most likelihood going to target Ruby 2.2.

Before the exact minimum version is fully decided, @arthurnn [suggests](https://github.com/rails/rails/pull/17830#issuecomment-64940383)
that **at least** version 2.1.0 **must** be required by the `gemspec` files.
Merge pull request #17830 from claudiob/bump-required-ruby-version

Bump required Ruby version to 2.1.0
Merge pull request #17816 from byroot/prevent-numeric-to-s-to-allocate-an-array

Prevent Numeric#to_s from allocating an array
adds missing period in test.rb [ci skip]
Pass symbol as an argument instead of a block
Merge pull request #16833 from sferik/symbol_to_proc

Pass symbol as an argument instead of a block
Pure rack apps can be mounted with a name

See https://github.com/rails/rails/commit/9b15828b5c347395b42066a588c88e5eb4e72279#commitcomment-8764492
Bump ruby version to 2.1.0 in rails.gemspec too.
Merge pull request #17846 from biow0lf/bump-ruby-version

Bump ruby version to 2.1.0 in rails.gemspec too.
Fix link in documentation. [ci skip]
Merge pull request #17848 from biow0lf/fix-link-in-action_view-base

Fix link in documentation. [ci skip]
Merge pull request #17823 from byroot/fix-mount-rack-apps-with-as

Pure rack apps can be mounted with a name
Stop using `Arel::Table.engine`

We never actually make use of it on the table, since we're constructing
the select manager manually. It looks like if we ever actually were
grabbing it from the table, we're grossly misusing it since it's meant
to vary by AR class.

Its existence on `Arel::Table` appears to be purely for convenience
methods that are never used outside of tests. However, in production
code it just complicates construction of the tables on the rails side,
and the plan is to remove it from `Arel::Table` entirely. I'm not
convinced it needs to live on `SelectManager`, etc either.