Users of other SCM's can now generate rails
apps that will add the "empty" directories to source control,
but will not have a useless .gitignore or mis-named .gitkeep
files.

* Change `rails new` and `rails plugin new` generators to name
  the `.gitkeep` as `.keep` in a more SCM-agnostic way.

* Change `--skip-git` option to only skip the `.gitignore` file
  and still generate the `.keep` files.

* Add `--skip-keeps` option to skip the `.keep` files.

It closes #2800.

move validation to AR

The cause of the previous revert was bug in bundler that made it hard to
make railties test work. Fix for bundler was recently pushed to github,
so now we can safely get back to the original commit.

This reverts commit 0f5cc34a.

This functionality will be available from gem
`active_record-session_store` instead.

It's not really a good idea to have this as a global config option. We
should allow people to specify the behaviour per association.

There will now be two new values:

* :dependent => :restrict_with_exception implements the current
  behaviour of :restrict. :restrict itself is deprecated in favour of
  :restrict_with_exception.
* :dependent => :restrict_with_error implements the new behaviour - it
  adds an error to the owner if there are dependent records present

See #4727 for the original discussion of this.

Revert "The application generator generates `public/humans.txt` with some basic data". I dont consider this something most people is going to want most of the time. If you want to add it in your own app, knock yourself out. But it doesnt belong in Rails imo

For instance, running

    rails g migration CreateMediaJoinTable artists musics:uniq

will create a migration with

    create_join_table :artists, :musics do |t|
      # t.index [:artist_id, :music_id]
      t.index [:music_id, :artist_id], unique: true
    end

AddXXXToYYY/RemoveXXXFromYYY migrations are produced with references
statements, for instance

    rails g migration AddReferencesToProducts user:references
supplier:references{polymorphic}

will generate the migration with:

    add_reference :products, :user, index: true
    add_reference :products, :supplier, polymorphic: true, index: true

For instance,

    $ rails g model Product supplier:references{polymorphic}

generate model with `belongs_to :supplier, polymorphic: true` association and appropriate migration.

Also fix model_generator_test.rb#L196 and #L201

(closes #6672)

if we are passing -T which is skip_test_unit

See issue #6673 for more details.

I saw that we are not creating dummy app even if
we do skip_test_unit.

Fixes #6673

f4d7af67

This reverts commit fa6d921e.

Reason: Not a fan of such massive changes. We usually close such changes
if made to Rails master as a pull request. Following the same principle
here and reverting.

[ci skip]

The Gemfile of new application uses ruby 1.9 hashes. Gem method of
generators should use them too. It prevents from mixing two kinds of
syntax in one file.

Using require in development mode will prevent required files from
reloading, even if they're changed. In order to keep namespaced
application_controller reloadable, we need to use require_dependency
instead of require.

In development mode, dependencies are loaded dynamically at runtime,
using `const_missing`. Because of that, when one of the constants is
already loaded and `const_missing` is not triggered, user can end up
with unexpected results.

Given such file in an Engine:

```ruby
module Blog
  class PostsController < ApplicationController
  end
end
```

If you load it first, before loading any application files, it will
correctly load `Blog::ApplicationController`, because second line will
hit `const_missing`. However if you load `ApplicationController` first,
the constant will be loaded already, `const_missing` hook will not be
fired and in result `PostsController` will inherit from
`ApplicationController` instead of `Blog::ApplicationController`.

Since it can't be fixed in `AS::Dependencies`, the easiest fix is to
just explicitly load application controller.

closes #6413

For future reference, this is the regex I used: ^\s*#\s*\n(?!\s*#). Replace
with the first match, and voilà! Note that the regex matches a little bit too
much, so you probably want to `git add -i .` and go through every single diff
to check if it actually should be changed.

Minitest uses different signature for assert_no_match, so we have to
swap arguments.

Reverted changes:
  f3482a9f Fix tests in railties
  5904295b improve #6318
  aed906af prevent using already loaded Gemfile for 'bundle install'

In order to fix this, we need a fix in bundler related to GEM_PATH,
which will allow to run tests properly. I will get this changes back
when it happens.

Since `bundle install` was fixed in `rails plugin new`, it
now requires `rails 4.0.0.beta` version in filesystem when
running tests. Instead of providing it, we can run tested
command with `--dev` option, to use rails from the local
directory.