Update README.md

Author: chris-smith

README.md

@@ -1,5 +1,63 @@
 # rosnodejs [![Build Status](https://travis-ci.org/RethinkRobotics-opensource/rosnodejs.svg)](https://travis-ci.org/RethinkRobotics-opensource/rosnodejs)
 
+## Start a node
+```
+const rosnodejs = require('rosnodejs');
+rosnodejs.initNode('/my_node')
+.then(() => {
+  // do stuff
+});
+```
+
+## Publish/Subscribe
+```
+const nh = rosnodejs.nh;
+const sub = nh.subscribe('/chatter', 'std_msgs/String', (msg) => {
+  console.log('Got msg on chatter: %j', msg);
+});
+
+const pub = nh.advertise('/chatter', 'std_msgs/String');
+pub.publish({ data: "hi" });
+```
+
+## Services
+```
+const service = nh.advertiseService('/add_two_ints', 'beginner_tutorials/AddTwoInts', (req, resp) => {
+  res.sum = req.a + req.b;
+  return true;
+});
+
+const client = nh.serviceClient('/add_two_ints', 'beginner_tutorials/AddTwoInts');
+client.call({a: 1, b: 2});
+```
+
+## Params
+```
+nh.setParam('val', 2);
+nh.getParam('val')
+.then((val) => {
+  // do stuff
+});
+```
+## Messages
+```
+const sensorMsgs = rosnodejs.require('sensor_msgs');
+
+const image = new sensorMsgs.msg.Image();
+const temperature = new sensorMsgs.msg.Temperature({ temperature: 32 });
+
+const SetCameraInfo = sensorMsgs.srv.SetCameraInfo;
+const setRequest = new SetCameraInfo.Request();
+
+// messages can be used when advertising/subscribing
+const StringMsg = rosnodejs.require('std_msgs').msg.String;
+const sub = nh.subscribe('/chatter', StringMsg, (msg) => { ... });
+const pub = nh.advertise('/chatter', StringMsg);
+
+const AddTwoInts = rosnodejs.require('beginner_tutorials').srv.AddTwoInts;
+const service = nh.advertiseService('/add_two_ints', AddTwoInts, (req, resp) => { ... });
+const client = nh.serviceClient('/add_two_ints', AddTwoInts);
+```
 
 ## Run the turtlesim example
 
@@ -22,3 +80,14 @@ or, if you are running an older version of node:
 npm run compile
 node dist/examples/turtle.js
 ```
+
+## Catkin-Like
+Checkout [`rosnodejs_examples`](https://github.com/RethinkRobotics-opensource/rosnodejs_examples) for a more catkin-inspired take on using `rosnodejs`.
+
+## Inspired By
+`rosnodejs` was inspired by other work that you can learn more about here
+- [roscpp & rospy](https://github.com/ros/ros_comm)
+- [Robots as web services](http://ieeexplore.ieee.org/document/5980464/?tp=&arnumber=5980464&url=http:%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D5980464)
+- [ROSBridge](https://github.com/RobotWebTools/rosbridge_suite)
+- [roslibjs](https://github.com/RobotWebTools/roslibjs)
+