Added support for Ruby v2 Specialization (#1101)

* Added support for Ruby v2 Specialization
* Added ruby v2 example with builder code

environments/ruby/builder/Dockerfile

@@ -0,0 +1,12 @@
+ARG BUILDER_IMAGE=fission/builder:latest
+FROM ${BUILDER_IMAGE}
+
+FROM ruby:2.6.1-alpine3.9
+COPY --from=0 /builder /builder
+
+RUN apk update
+RUN apk add --no-cache ruby ruby-dev ruby-bundler build-base
+
+ADD defaultBuildCmd /usr/local/bin/build
+
+EXPOSE 8001

environments/ruby/builder/defaultBuildCmd

@@ -0,0 +1,9 @@
+#!/bin/sh
+set -euxo pipefail
+
+if [ -f ${SRC_PKG}/Gemfile.lock ]
+then 
+	cd $SRC_PKG
+	bundle install --deployment
+fi
+cp -r ${SRC_PKG} ${DEPLOY_PKG}