add post-install func

words/index.rkt

@@ -70,4 +70,7 @@
   (fasl->s-exp (open-input-file (and
                                  (unless (file-exists? wordidx-file)
                                    (regenerate-word-index!))
-                                 wordidx-file))))
+                                 wordidx-file))))
+
+(define (post-installer home-dir)
+  (regenerate-word-index!))

words/info.rkt

@@ -0,0 +1,3 @@
+#lang info
+
+(define post-install-collection "index.rkt")