resolves #4 DUNE doesn't work on MacOS/Darwin

bootstrap.sh

@@ -1,4 +1,9 @@
-#! /usr/bin/bash
+#!/usr/bin/env bash
 
 SDIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
-docker build --build-arg USER_ID=$(id -u ${USER}) --build-arg GROUP_ID=$(id -g ${USER})  -t dune $SDIR
+GROUP_ID=$(id -g ${USER})
+# for mac users
+if [[ $(uname) == "Darwin" ]]; then
+  GROUP_ID=200
+fi
+docker build --build-arg USER_ID=$(id -u ${USER}) --build-arg GROUP_ID=${GROUP_ID}  -t dune $SDIR

dune

@@ -1,4 +1,4 @@
-#! /usr/bin/bash
+#!/usr/bin/env bash
 
 SDIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
 python3 $SDIR/src/dune $@