No need to add config for x_sendfile_header

Rack::Sendfile is loaded by default now
Added CheckPending middleware in default

As this middleware comes by default in a new
rails app

Added test to check omit for CheckPending when

Active Record is not included.
Merge pull request #11448 from arunagw/updated_middleware_test

No need to add config for x_sendfile_header
Remove deprecation warning from attribute_missing 

for attributes that are columns.
Merge pull request #11282 from arunagw/deprecation-removed-attribute-missing-activerecord

Remove deprecated `attribute_missing`.
Do not re-save destroyed association on saving parent object

Closes #11450
Merge pull request #11451 from jetthoughts/11450_do_not_resave_destroyed_association

Do not re-save destroyed association on saving parent object
use arel rather than slapping together SQL strings
reorder bind parameters when merging relations
removing useless assingment
save another array allocation
Lock mysql2 version to 0.3.11 since 0.3.12 is failing right now. Check #11457 for details
Added generated unit test for generator generator and new test:generators rake task included in test:all rake task.
Merge pull request #11419 from simi/generator_generator_test

Added generated unit test for generator generator.
Add `#any_of` query method to active_record

This method is inspired by [any_of from
mongoid](http://two.mongoid.org/docs/querying/criteria.html#any_of).

It allows to compute an `OR` like query that leverages AR's `#where` syntax:

    manual_removal = User.where(id: params[:users][:destroy_ids])
    users = User.any_of(manual_removal, "email like '%@example.com'", {banned: true}).destroy_all

It can be used directly on model class, or through an association, or
behind an other relation.

    manual_removal = User.where(id: params[:users][:destroy_ids])
    User.any_of(manual_removal, "email like '%@example.com'", {banned: true})
    @company.users.any_of(manual_removal, "email like '%@example.com'", {banned: true})
    User.where(offline: false).any_of( manual_removal, "email like '%@example.com'", {banned: true})

Its main purpose is to both :

* remove the need to write a sql string when we want an `OR`
* allow to write dynamic `OR` queries, which would be a pain with a string

There's also a negative version, `#none_of`. This will return all active
users :

    banned_users = User.where(banned: true)
    unconfirmed_users = User.where("confirmed_at IS NULL")
    active_users = User.none_of(banned_users, unconfirmed_users)