FEATURE: add new 'convert to staff message' in post wrench menu

spec/models/post_revision_spec.rb

@@ -70,4 +70,12 @@ describe PostRevision do
     changes[:current_wiki].should be_true
   end
 
+  it "can find post_type changes" do
+    r = create_rev("post_type" => [1, 2])
+
+    changes = r.post_type_changes
+    changes[:previous_post_type].should == 1
+    changes[:current_post_type].should == 2
+  end
+
 end