fixing arel requirements for released arel

Gemfile

@@ -5,7 +5,7 @@ gemspec
 if ENV['AREL']
   gem "arel", :path => ENV['AREL']
 else
-  gem "arel", :git => "git://github.com/rails/arel.git"
+  gem "arel", '~> 2.1.0'
 end
 
 gem "rack", :git => "git://github.com/rack/rack.git"

activerecord/activerecord.gemspec

@@ -22,6 +22,6 @@
 
   s.add_dependency('activesupport', version)
   s.add_dependency('activemodel',   version)
-  s.add_dependency('arel',          '~> 2.0.2')
+  s.add_dependency('arel',          '~> 2.1.0')
   s.add_dependency('tzinfo',        '~> 0.3.23')
 end