Move definiton of liquid legacy tags into the Legacy module.

This is required to retaiun the definition in development mode as the module
is stragely reloaded.

lib/chili_project/liquid/legacy.rb

@@ -54,5 +54,13 @@ module ChiliProject
         end
       end
     end
+
+    # FIXME: remove the deprecated syntax for 4.0, provide a way to migrate
+    # existing pages to the new syntax.
+    #
+    # See ChiliProject::Liquid::Tags for the registration of the tags.
+    Legacy.add('child_pages', :tag)
+    Legacy.add('hello_world', :tag)
+    Legacy.add('include', :tag)
   end
 end

lib/chili_project/liquid/tags.rb

@@ -31,8 +31,3 @@ module ChiliProject::Liquid
   end
 end
 
-# FIXME: remove the deprecated syntax for 4.0, provide a way to migrate
-# existing pages to the new syntax.
-ChiliProject::Liquid::Legacy.add('child_pages', :tag)
-ChiliProject::Liquid::Legacy.add('hello_world', :tag)
-ChiliProject::Liquid::Legacy.add('include', :tag)