Merge pull request #167 from sharifelgamal/upgrade

Explicitly call apt-get upgrade to get newest versions of packages

Author: sharifelgamal

ruby-ubuntu16/Dockerfile

@@ -76,6 +76,7 @@ RUN apt-get update -y \
         systemtap \
         tzdata \
     && apt-get install -y -q --no-install-recommends libgit2-dev \
+    && apt-get upgrade -yq \
     && apt-get clean \
     && rm -f /var/lib/apt/lists/*_* \
     && mkdir -p /opt/nodejs \