Do not use for..in operator for iterate over an array

Change-Id: I2d73e80a313adb8a22488dd8ddaa1034ee4dd7ee
diff --git a/src/server.js b/src/server.js
index 6f70d3a..182985a 100644
--- a/src/server.js
+++ b/src/server.js
@@ -51,9 +51,9 @@
 
             // load built-in workflows
             let workflows = workflowLoader.loadAllWorkflows();
-            for(let workflow in workflows) {
+            workflows.forEach((workflow) => {
                 eventrouter.addWorkflow(workflow);
-            }
+            });
         });
         app.server = server;
         return server;