added ruby (#85)

* added ruby

* Updates from code review

* updates from code review

README.md

@@ -144,6 +144,7 @@ These derived images include a set of standard capabilities that enable many of
 - Node.js 8.10.0 LTS
 - Powershell Core v6.0.1
 - Python 2.7.12 and 3.5.2
+- Ruby 1.9.3 (14.04) or 2.3.1 (16.04)
 - Scala sbt-extras
 - Subversion 1.9.3
 

ubuntu/14.04/standard/Dockerfile

@@ -140,6 +140,11 @@ RUN apt-get update \
     python3-pip \
  && rm -rf /var/lib/apt/lists/*
 
+# Install Ruby
+RUN apt-get update \
+ && apt-get install -y ruby ruby-dev ruby-bundler \
+ && rm -rf /var/lib/apt/lists/*
+
 # Install Scala build tools
 RUN curl -s https://raw.githubusercontent.com/paulp/sbt-extras/master/sbt > /usr/local/bin/sbt \
  && chmod 0755 /usr/local/bin/sbt

ubuntu/16.04/standard/Dockerfile

@@ -140,6 +140,11 @@ RUN apt-get update \
     python3-pip \
  && rm -rf /var/lib/apt/lists/*
 
+# Install Ruby
+RUN apt-get update \
+ && apt-get install -y ruby ruby-dev ruby-bundler \
+ && rm -rf /var/lib/apt/lists/*
+
 # Install Scala build tools
 RUN curl -s https://raw.githubusercontent.com/paulp/sbt-extras/master/sbt > /usr/local/bin/sbt \
  && chmod 0755 /usr/local/bin/sbt

ubuntu/standard/Dockerfile.template

@@ -140,6 +140,11 @@ RUN apt-get update \
     python3-pip \
  && rm -rf /var/lib/apt/lists/*
 
+# Install Ruby
+RUN apt-get update \
+ && apt-get install -y ruby ruby-dev ruby-bundler \
+ && rm -rf /var/lib/apt/lists/*
+
 # Install Scala build tools
 RUN curl -s https://raw.githubusercontent.com/paulp/sbt-extras/master/sbt > /usr/local/bin/sbt \
  && chmod 0755 /usr/local/bin/sbt