avoid using alias in generators

Ruby's alias produces public methods, causing a spurious Thor task
to be created.  For example, this is the reason MigrationGenerator
currently has two tasks:

    > ActiveRecord::Generators::MigrationGenerator.all_tasks.keys
    => ["singular_name", "create_migration_file"]

singular_name was meant to be an attribute, not a task.  Because it's
public, it gets called as a task every time the generator is invoked.

The fix is to ensure all generator methods have the correct
visibility.
Fixes URL generation with trailing_slash: true

URL generation with trailing_slash: true was adding a trailing slash
after .:format

    Routes.draw do
      resources :bars
    end

    bars_url(trailing_slash: true, format: 'json')
      # => /bars.json/

This commit removes that extra trailing slash
Merge pull request #14986 from dlangevin/trailing-slash-url-generation

Fixes URL generation with trailing_slash: true

Conflicts:
	actionpack/lib/action_dispatch/http/url.rb
Add documentation for using Rails with a reverse proxy
Merge pull request #13988 from zzak/guides_configuring_reverse_proxy

[Guides] Add documentation for using Rails with a reverse proxy [ci skip]
Merge pull request #9083 from bronson/patch-1

avoid using alias in generators
fixed capitalization
Add FIXME note about the thor bug
Merge pull request #15298 from ShunsukeAida/fix_capitalization

fixed capitalization [ci skip]
rake stats for engines
documentation fix
Merge pull request #15264 from Gaurav2728/gaurav-documentation_fix

documentation link fix and removing unused reader
Merge pull request #15299 from andriytyurnikov/engine_friendly_rake_stats

rake stats for engines
Improve readability of Explain Queries table in guides [ci skip]
Merge pull request #15303 from JohnKellyFerguson/guides-ar-querying

Improve readability of Explain Queries table in guides
integration tests do not need to load fixtures by hand

I don't know when this changed, checked back up to 3.2 and integration
tests instantiate fixtures just fine.
Update all Rails 4.1.0 references in guides to 4.1.1 [ci skip]
Merge pull request #15304 from JohnKellyFerguson/guides-4.1.1

Update all Rails 4.1.0 references in guides to 4.1.1 [ci skip]
unwrap the constraints object on initialization, eliminate loops

Unwrap Constraints objects.  I don't actually think it's possible
to pass a Constraints object to this constructor, but there were
multiple places that kept testing children of this object.  I
*think* they were just being defensive, but I have no idea.
Remove unnecessary require of Minitest.

Minitest has already been required when calling Minitest.autorun.