Clean up

README.md

@@ -74,9 +74,17 @@ Visit `localhost:8080` in web browser
 
     $ make lint
 
+### print out pygments styles
+
+    $ pygmentize -S STYLE -f formatter
+
+example:
+
+    $ pygmentize -S default -f html
+
 ## gotchas
 
-### What is `cosmo failed: [string "..."]:62: cannot resume dead coroutine`?
+### What is error `cosmo failed: [string "..."]:62: cannot resume dead coroutine`?
 
 If you call `cosmo.yield`, your function **must** return `nil`! If you forget
 to return `nil`, you will see this cryptic error:
@@ -84,6 +92,14 @@ to return `nil`, you will see this cryptic error:
     Error: index.html -> html/index.html: cosmo failed: [string "..."]:62: cannot resume dead coroutine
     make: *** [Makefile:6: build] Error 1`
 
+### What is error `calling 'load_cache' on bad self`?
+
+    moon: .../local/openresty/luajit/share/lua/5.1/sitegen/common.lua:41:
+    /usr/local/openresty/luajit/share/lua/5.1/sitegen/cache.lua:99: calling
+    'load_cache' on bad self (table expected, got userdata) stack traceback:
+
+Delete your `.sitegen_cache` file.
+
 ## todo
 
 * draft documents