Updated README documentation (#19)

Author: Justin Boswell

README.md

@@ -1,7 +1,115 @@
-## AWS IoT SDK for Node.js v2
+# AWS IoT SDK for Javascript v2
 
-Next generation AWS IoT Client SDK for Node.js using the AWS Common Runtime
+Next generation AWS IoT Client SDK for Javascript.
 
-## License
+This project is in **DEVELOPER PREVIEW** while we gather feedback on
+interfaces and use cases. Please file issues and feature requests.
+Expect breaking API changes as we incorporate feedback.
+Until this project is promoted to General Availability, we advise you use the
+[previous SDK](https://github.com/aws/aws-iot-device-sdk-js)
+for a stable development environment.
 
-This library is licensed under the Apache 2.0 License. 
+This SDK is built on the AWS Common Runtime, a collection of libraries
+([1](https://github.com/awslabs/aws-c-common),
+[2](https://github.com/awslabs/aws-c-io),
+[3](https://github.com/awslabs/aws-c-mqtt),
+[4](https://github.com/awslabs/aws-c-http),
+[5](https://github.com/awslabs/aws-c-cal) ...) written in C to be
+cross-platform, high-performance, secure, and reliable. The libraries are bound
+to JS by the [awscrt](https://github.com/awslabs/aws-crt-nodejs) package.
+
+The aws-crt package can be installed via npm 
+```
+npm install aws-crt
+```
+
+Integration with AWS IoT Services such as
+[Device Shadow](https://docs.aws.amazon.com/iot/latest/developerguide/iot-device-shadows.html)
+and [Jobs](https://docs.aws.amazon.com/iot/latest/developerguide/iot-jobs.html)
+is provided by code that been generated from a model of the service.
+
+# Installation
+## Minimum Requirements
+*   Node 10.x+
+
+## Install from npm
+```
+npm install aws-iot-device-sdk-v2
+```
+
+## Build from source
+```
+npm install
+```
+
+# Samples
+
+## node/pub_sub
+This sample uses the
+[Message Broker](https://docs.aws.amazon.com/iot/latest/developerguide/iot-message-broker.html)
+for AWS IoT to send and receive messages
+through an MQTT connection. On startup, the device connects to the server,
+subscribes to a topic, and begins publishing messages to that topic.
+The device should receive those same messages back from the message broker,
+since it is subscribed to that same topic.
+Status updates are continually printed to the console.
+
+Source: `samples/node/pub_sub`
+
+Run the sample like this:
+```
+npm install
+node dist/index.js --endpoint <endpoint> --root-ca <file> --cert <file> --key <file>
+```
+
+Your Thing's
+[Policy](https://docs.aws.amazon.com/iot/latest/developerguide/iot-policies.html)
+must provide privileges for this sample to connect, subscribe, publish,
+and receive.
+<details>
+<summary>(see sample policy)</summary>
+<pre>
+{
+  "Version": "2012-10-17",
+  "Statement": [
+    {
+      "Effect": "Allow",
+      "Action": [
+        "iot:Publish",
+        "iot:Receive"
+      ],
+      "Resource": [
+        "arn:aws:iot:<b>region</b>:<b>account</b>:topic/samples/test"
+      ]
+    },
+    {
+      "Effect": "Allow",
+      "Action": [
+        "iot:Subscribe"
+      ],
+      "Resource": [
+        "arn:aws:iot:<b>region</b>:<b>account</b>:topicfilter/samples/test"
+      ]
+    },
+    {
+      "Effect": "Allow",
+      "Action": [
+        "iot:Connect"
+      ],
+      "Resource": [
+        "arn:aws:iot:<b>region</b>:<b>account</b>:client/samples-client-id"
+      ]
+    }
+  ]
+}
+</pre>
+</details>
+
+## node/basic_discovery
+
+This sample intended for use directly with the 
+[Getting Started with AWS IoT Greengrass](https://docs.aws.amazon.com/greengrass/latest/developerguide/gg-gs.html) guide.
+
+# License
+
+This library is licensed under the Apache 2.0 License.