Updated to reference rosetteapi/docker-nodejs

- Removed docker directory
- Updated README

Author: Chris Park

README.md

@@ -7,6 +7,15 @@ This is the Rosette API client binding for node.js.
 ## Getting Started
 Install the module with: `npm install rosette-api`
 
+## Docker ##
+A Docker image for running the examples against the compiled source library is available on Docker Hub.
+
+Command: `docker run -e API_KEY=api-key -v "path-to-local-csharp-dir:/source" rosetteapi/docker-nodejs`
+
+Additional environment settings:
+`-e ALT_URL=<alternative URL>`
+`-e FILENAME=<single filename>`
+
 
 ## Example using the Rosette API language detection endpoint
 ```javascript