Add Dockerfile and notes to README.

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 $PWD/dist:/build/dist swagger-ui-builder
+#
+###
+
+FROM    ubuntu:14.04
+MAINTAINER dnephin@gmail.com
+
+ENV     DEBIAN_FRONTEND noninteractive
+
+RUN     apt-get update && apt-get install -y git npm nodejs openjdk-7-jre
+RUN     ln -s /usr/bin/nodejs /usr/local/bin/node
+
+WORKDIR /build
+ADD     package.json    /build/package.json
+RUN     npm install
+ADD     .   /build
+CMD     PATH=$PATH:node_modules/.bin cake dist