Add a Dockerfile to make Linux builds.

Author: JMLX42

Dockerfile

@@ -0,0 +1,7 @@
+FROM ubuntu:18.04
+
+RUN apt-get update && \
+    apt-get install -y software-properties-common cmake libboost1.62-dev && \
+    add-apt-repository ppa:ubuntu-toolchain-r/test && \
+    apt-get install -y g++-8 && \
+    update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-8 60 --slave /usr/bin/g++ g++ /usr/bin/g++-8