Merge pull request #474 from knapo/master

Remove Rails 3.1 `read_inheritable_attribute` deprecation and add .rvmrc to gitignore.

.gitignore

@@ -8,3 +8,4 @@ capybara*.html
 *.rbc
 .bundle
 *SPIKE*
+.rvmrc

lib/paperclip.rb

@@ -341,7 +341,7 @@ module Paperclip
     # Returns the attachment definitions defined by each call to
     # has_attached_file.
     def attachment_definitions
-      read_inheritable_attribute(:attachment_definitions)
+      inheritable_attributes[:attachment_definitions]
     end
   end