add notes on how to blog..

BLOG.md

@@ -0,0 +1,26 @@
+How to blog
+===========
+
+If a code block is in a list item like:
+```
+1. This is a list item with source:
+   ```
+   source
+   ```
+```
+
+Do not use the above, but instead, use:
+```
+1. This is a list item with source:
+   <pre class="fullwidth"><code>
+   source
+   </code></pre>
+```
+
+If you want a code block w/ line numbers, it can only be done at the
+parent level via:
+```
+  ``` { .shell .showlines }
+  some lines
+  ````
+```