update readme and make interactivity settable

README.md

@@ -1,3 +1,51 @@
 Windshaft-CartoDB
 ==================
 
+This is the CartoDB map tiler.
+
+Look at lob/cartodb/server_options to see how we configure windshaft
+
+
+Install
+-------
+```
+git clone
+npm install
+node app.js [development | production]
+```
+
+
+Core features
+-------------
+* reads dbname from subdomain and cartodb redis for pretty tile urls
+* configures windshaft to publish cartodb_id as the interactivity layer
+* gets the default geometry type from the cartodb redis store
+* provides an ultra basic infowindow endpoint for windshaft
+
+
+URLs
+----
+
+**TILES**
+[GET] subdomain.cartodb.com/tiles/:table_name/:z/:x/:y.[png|png8|grid.json]
+
+Args:
+* sql - plain SQL arguments
+* interactivity - specify the column to use in UTFGrid
+* cache_buster - if needed you can add a cachebuster to make sure you're rendering new
+* geom_type - override the cartodb default
+
+**STYLE**
+[GET/POST] subdomain.cartodb.com/tiles/:table_name/style
+
+Args:
+* style - the style in CartoCSS you want to set
+
+**INFOWINDOW**
+[GET] subdomain.cartodb.com/tiles/:table_name/infowindow
+
+Args:
+* infowindow - returns contents of infowindow from CartoDB.
+
+
+All GET requests are wrappable with JSONp using callback argument, including the UTFGrid map tile call.

lib/cartodb/server_options.js

@@ -27,8 +27,8 @@ me.req2params = function(req, callback){
     // bring all query values onto req.params object
     _.extend(req.params, req.query);
 
-    // for cartodb, ensure interactivity is cartodb_id
+    // for cartodb, ensure interactivity is cartodb_id or user specified
-    req.params.interactivity = 'cartodb_id';
+    req.params.interactivity = req.params.interactivity || 'cartodb_id';
 
     Step(
         function getDatabase(){