Improve README.md and add new gif

-#### express-monitor
-A module based on Socket.io and Chart.js to report realtime server metrics for Express-based node servers.
+# express-monitor
+A module based on Socket.io and Chart.js to report realtime server metrics for Express-based node servers. More Node frameworks coming soon.
 
 
 ![Monitoring Page](/out.gif?raw=true "Monitoring Page")
 ![Monitoring Page](/out.gif?raw=true "Monitoring Page")
 
 
-### How to use it (in progress)
+## How to use it (in progress)
 1. Add this as a dependency (will be on NPM soon)
 1. Add this as a dependency (will be on NPM soon)
 2. Before any other middleware or router add following line: 
 2. Before any other middleware or router add following line: 
 `app.use(expressMonitor());`
 `app.use(expressMonitor());`
 3. Run server and to go `/status`
 3. Run server and to go `/status`
 
 
+## Options
+
+Monitor can be configured by passing options object into `expressMonitor` constructor.
+ 
+Default config:
+```
+path: '/status',
+socketPort: 41338, // Port for Socket.io communication
+spans: [{
+  interval: 1,     // Every second
+  retention: 60    // Keep 60 datapoints in memory
+}, {
+  interval: 5,     // Every 5 seconds
+  retention: 60
+}, {
+  interval: 15,    // Every 15 seconds
+  retention: 60
+}]
+
+```
+
+## License
+
+[MIT License](https://opensource.org/licenses/MIT) © Rafal Wilinski
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