Reproducible-SW-environment-with-Spack.md

 # Initial setup:
 Clone and source spack  (you can skip the clone step if spack is already installed) in the home directory:
+```
+git clone https://github.com/spack/spack.git -b v0.17.1 ~/spack
+source ~/spack/share/spack/setup-env.sh
+```