Use annotated git tags for release task

RELEASING_RAILS.rdoc

@@ -110,7 +110,7 @@ what to do in case anything goes wrong:
 
     $ rake all:build
     $ git commit -am'updating RAILS_VERSION'
-    $ git tag -a -m'tagging rc release' v3.0.10.rc1
+    $ git tag -m 'v3.0.10.rc1 release' v3.0.10.rc1
     $ git push
     $ git push --tags
     $ for i in $(ls pkg); do gem push $i; done

tasks/release.rb

@@ -120,7 +120,7 @@ namespace :all do
   end
 
   task :tag do
-    sh "git tag -a #{tag}"
+    sh "git tag -m '#{tag} release' #{tag}"
     sh "git push --tags"
   end