doc on chart

doc/index.html

@@ -89,6 +89,11 @@ document in progress (forthcoming API v 1.0).
 
 <a href="transfer.html">The GF Transfer language</a> document.
 
+<p>
+
+<a href="gf-compiler.png">Chart of GF grammar compiler phases</a>.
+
+
 
 <h2>Embedding GF grammars in computer programs</h2>