Shrink dockerfile: replace ubuntu by alpine

Author: xtofl

docker/Dockerfile

@@ -1,6 +1,6 @@
-FROM ubuntu:18.04
+FROM alpine:3
 
-RUN apt update
-RUN apt install -y gcc-8 cmake
-RUN apt install -y vim git
-RUN apt install -y g++-8
+RUN apk update
+RUN apk add make cmake>=3.11 g++>=9
+RUN apk add vim git
+RUN apk add clang

docker/build-container.bat

@@ -1 +1 @@
-docker build --tag cpp11training %~dp0
+docker build --tag cpp11training %~dp0

docker/build-container.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+docker build --tag cpp11training $(cd $(dirname $0); pwd)