Add Nate Johnston blog to Planet OpenStack

I think it's a good time to start blogging again.

Change-Id: I0934c3b5ea30560f32680b26c9bc4cdbbf3a2fd4

planet.ini

@@ -1360,3 +1360,8 @@ nick = martbhell
 
 [https://cloud.blog.csc.fi/feeds/posts/default/-/openstack]
 name = CSC.fi Cloud Blog
+
+[https://natejohnston.info/categories/openstack/index.xml]
+name = Nate Johnston
+face = njohnston.jpg
+nick = njohnston