Add messaging for build;

index.js

@@ -81,9 +81,22 @@ var handlers = {
     },
 
     build: function(body) {
-        console.log('build event NYI because not documented');
-        console.log(body);
-        return null;
+
+        var id = body.build_id;
+        var status = body.build_status;
+
+        var isFinished = body.build_finished_at !== null;
+        var duration = body.build_duration;
+
+        var projectName = body.project_name;
+        var stage = body.build_stage;
+
+        var msg = [];
+        msg.push(projectName + ': build #' + id + ' (' + stage + ') changed status: ' + status);
+        if (isFinished)
+            msg.push('build finished in ' + duration + ' seconds. ');
+
+        return msg;
     }
 
 };