rake rails:freeze:edge should place the git revision into a REVISION file

Hey there, this is a really minor one,

but a minor thing that is a bit annoying.

At the moment rake rails:freeze:edge does the following downloads a zip extracts the zip touches a file called REVISION_ce03... (or whatever the revision was)

this leaves us with a git changeset that looks a bit ugly;

matthew@rubuntu:~/code/jimgit$ git status
# On branch master
# Changed but not updated:
#   (use "git add/rm <file>..." to update what will be committed)
#
#       deleted:    vendor/rails/REVISION_a1fb57aa6940253dbed5423ac3e064db272eab2a
#       modified:   vendor/rails/actionpack/lib/action_controller/base.rb
#       modified:   vendor/rails/actionpack/lib/action_controller/dispatcher.rb
#       modified:   vendor/rails/actionpack/lib/action_controller/integration.rb
#       modified:   vendor/rails/actionpack/lib/action_controller/middleware_stack.rb
#       modified:   vendor/rails/actionpack/lib/action_controller/request.rb
#       modified:   vendor/rails/actionpack/lib/action_controller/request_parser.rb
#       modified:   vendor/rails/actionpack/lib/action_controller/rescue.rb
#       modified:   vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb
#       modified:   vendor/rails/actionpack/test/controller/dispatcher_test.rb
#       modified:   vendor/rails/actionpack/test/controller/integration_upload_test.rb
#       modified:   vendor/rails/actionpack/test/controller/request_test.rb
#       modified:   vendor/rails/actionpack/test/controller/rescue_test.rb
#       modified:   vendor/rails/actionpack/test/template/asset_tag_helper_test.rb
#       modified:   vendor/rails/activesupport/CHANGELOG
#       modified:   vendor/rails/activesupport/lib/active_support/time_with_zone.rb
#       modified:   vendor/rails/activesupport/test/core_ext/time_with_zone_test.rb
#       modified:   vendor/rails/railties/lib/initializer.rb
#       modified:   vendor/rails/railties/test/console_app_test.rb
#
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#       vendor/rails/REVISION_ce706b4b9be03a3f2e7d11438e6550d64c5f4461
#       vendor/rails/actionpack/test/controller/middleware_stack_test.rb
#       vendor/rails/actionpack/test/fixtures/multipart/hello.txt

namely; we have to delete the old REVISION file and add the new one.

I think having a single REVISION file which contains the name of the latest commit is the best way to proceed.

Attached in a patch to do this

-        touch "rails/REVISION_#{latest_revision}"
+        puts "Frozen to git revision #{latest_revision}"
+        File.open('rails/REVISION', 'w') do |revision|
+          revision.puts latest_revision
+        end