add usage.md

lib/sportdb/service/views/_usage.md

@@ -0,0 +1,32 @@
+%%%%%%%%%%%%%%%%%
+% NB: after generation add/patch w/ macro
+%
+%  replace
+%     http://footballdb.herokuapp.com/api/v1/event/en.2012_13/round/2
+%  with
+%     <%= url( '/' ) %>event/en.2012_13/round/2....  twice
+%%%%%%%%%
+
+## Usage
+
+In your hypertext (HTML) document using a plain vanilla cross-domain JavaScript
+request (using the JSONP technique):
+
+    <script>
+      function handleGames( json ) {
+         // Do something with the returned data
+      }
+    </script>
+
+    <script src="http://footballdb.herokuapp.com/api/event/en.2012_13/round/2?callback=handleGames"></script>
+
+
+Or using the jQuery library using the [`getJSON` function](http://api.jquery.com/jQuery.getJSON):
+
+    $.getJSON('http://footballdb.herokuapp.com/api/event/en.2012_13/round/2?callback=?', function(json) {
+      // Do something with the returned data
+    });
+
+Note: Add the `callback=?` query parameter to tell jQuery to use a cross-domain JSONP request.
+
+That's it.