Add Dockerfile and notes to README.

Author: dnephin

.dockerignore

@@ -0,0 +1,4 @@
+.git
+node_modules
+bower_components
+*.swp

Dockerfile

@@ -0,0 +1,22 @@
+###
+# swagger-ui-builder - https://github.com/wordnik/swagger-ui/
+# Container for building the swagger-ui static site
+#
+# Build: docker build -t swagger-ui-builder .
+# Run:   docker run -v $PWD/dist:/build/dist swagger-ui-builder
+#
+###
+
+FROM    ubuntu:14.04
+MAINTAINER [email protected]
+
+ENV     DEBIAN_FRONTEND noninteractive
+
+RUN     apt-get update && apt-get install -y git npm nodejs openjdk-7-jre
+RUN     ln -s /usr/bin/nodejs /usr/local/bin/node
+
+WORKDIR /build
+ADD     package.json    /build/package.json
+RUN     npm install
+ADD     .   /build
+CMD     PATH=$PATH:node_modules/.bin cake dist

README.md

@@ -38,6 +38,15 @@ You can rebuild swagger-ui on your own to tweak it or just so you can say you di
 4. npm run-script build
 5. You should see the distribution under the dist folder. Open ./dist/index.html to launch Swagger UI in a browser
 
+### Build using Docker
+
+To build swagger-ui using a docker container:
+
+```
+docker build -t swagger-ui-builder .
+docker run -v $PWD/dist:/build/dist swagger-ui-builder
+```
+
 ### Use
 Once you open the Swagger UI, it will load the [Swagger Petstore](http://petstore.swagger.wordnik.com/api/api-docs) service and show its APIs.  You can enter your own server url and click explore to view the API.