Adding extensions section, staring with the remarkable gem. Fixes mon…

…goid#7

content/docs/extensions.html.haml

@@ -0,0 +1,29 @@
+---
+title: Extensions
+author: Durran Jordan
+category: docs
+---
+.title Remarkable
+.text
+  %p
+    Brian Cardarella's
+    <a href="http://github.com/bcardarella/remarkable_mongoid">Remarkable</a>
+    gem provides a nice addition of RSpec matchers for Mongoid. It contains
+    the matchers shown below, plus all validation matchers from
+    <a href="http://github.com/remarkable/remarkable/tree/master/remarkable_activemodel">
+    Remarkable::ActiveModel</a>.
+
+  %pre
+    %code.language-ruby
+      :preserve
+        describe Person do
+
+          it { should reference_one :account }
+          it { should reference_many :posts }
+          it { should be_referenced_in :organization }
+          it { should embed_one :name }
+          it { should embed_many :addresses }
+          it { should be_embedded_in :group }
+
+          it { should validate_uniqueness_of :dob }
+        end

layouts/docs.haml

@@ -39,6 +39,7 @@
           %li= link_to_unless_current("Extras", "/docs/extras/")
           %li= link_to_unless_current("Rake Tasks", "/docs/rake/")
           %li= link_to_unless_current("Integration", "/docs/integration/")
+          %li= link_to_unless_current("Extensions", "/docs/extensions/")
           %li= link_to_unless_current("Upgrading", "/docs/upgrading/")
 
       = render "shared/footer"