prepare for 3.2 guides release :)

railties/guides/source/_welcome.html.erb

@@ -10,7 +10,7 @@
 </p>
 <% else %>
 <p>
-  These are the new guides for Rails 3.1 based on <a href="https://github.com/rails/rails/tree/<%= @version %>"><%= @version %></a>.
+  These are the new guides for Rails 3.2 based on <a href="https://github.com/rails/rails/tree/<%= @version %>"><%= @version %></a>.
   These guides are designed to make you immediately productive with Rails, and to help you understand how all of the pieces fit together.
 </p>
 <% end %>