[Rails] Allow compass extensions to be stored in the vendor/plugins/compass/extensions directory.

features/extensions.feature

@@ -0,0 +1,20 @@
+Feature: Extensions
+  In order to have an open source ecosystem for stylesheets
+  As a compass user
+  I can install extensions that others have created
+  And I can create and publish my own extensions
+
+  Scenario: Extensions directory for stand_alone projects
+    Given I am using the existing project in test/fixtures/stylesheets/compass
+    And the "extensions" directory exists
+    And and I have a fake extension at extensions/testing
+    When I run: compass --list-frameworks
+    Then the list of frameworks includes "testing"
+
+  Scenario: Extensions directory for rails projects
+    Given I'm in a newly created rails project: my_rails_project
+    And the "my_rails_project/vendor/plugins/compass/extensions" directory exists
+    And and I have a fake extension at my_rails_project/vendor/plugins/compass/extensions/testing
+    When I run: compass --list-frameworks
+    Then the list of frameworks includes "testing"
+

features/step_definitions/extension_steps.rb

@@ -0,0 +1,13 @@
+Given /^the "([^\"]*)" directory exists$/ do |directory|
+  FileUtils.mkdir_p directory
+end
+
+Given /^and I have a fake extension at (.*)$/ do |directory|
+  FileUtils.mkdir_p File.join(directory, 'stylesheets')
+  FileUtils.mkdir_p File.join(directory, 'templates/project')
+end
+
+Then /^the list of frameworks includes "([^\"]*)"$/ do |framework|
+  @last_result.split("\n").map{|f| f.strip}.should include(framework)
+end
+

lib/compass/app_integration/rails/configuration_defaults.rb

@@ -27,6 +27,10 @@ module Compass
           "/stylesheets"
         end
 
+        def default_extensions_dir
+          "vendor/plugins/compass/extensions"
+        end
+
       end
     end
   end