fix

lib/paperclip/glue.rb

@@ -8,7 +8,7 @@ module Paperclip
       base.extend ClassMethods
       base.send :include, Callbacks
       base.send :include, Validators
-      base.send :include, Schema
+      base.send :include, Schema if defined? ActiveRecord
 
       locale_path = Dir.glob(File.dirname(__FILE__) + "/locales/*.{rb,yml}")
       I18n.load_path += locale_path unless I18n.load_path.include?(locale_path)

spec/paperclip/attachment_spec.rb

@@ -1491,5 +1491,24 @@ describe Paperclip::Attachment do
     end
   end
 
+  context "Non ActiveRecord workflows" do
+    before do
+      # temporary take out AR
+      @ar_bak = Object.send(:remove_const, :ActiveRecord)
+    end
+
+    it "Can include glue without dependency on AR" do
+      klass = Object.const_set("SomeNonActiveRecordModel", Class.new)
+      klass.class_eval do
+        include Paperclip::Glue
+      end
+    end
+
+    after do
+      # put back AR
+      ActiveRecord = @ar_back
+    end
+  end
+
 end