Add entry for spack package manager

README.md

@@ -110,6 +110,7 @@
 * [EasyBuild](https://easybuild.readthedocs.org/en/latest/) - EasyBuild builds software and modulefiles for High Performance Computing (HPC) systems in an efficient way.
 * [environment-modules Lmod](https://www.tacc.utexas.edu/research-development/tacc-projects/lmod) - Lmod is a Lua based module system that easily handles the MODULEPATH Hierarchical problem.
 * [HPCBIOS](http://hpcbios.readthedocs.org/en/latest/) - HPCBIOS is an effort to setup a common, well-documented and reproducible, environment spanning across multiple HPC systems & sites, *inclusive* of documentation.
+* [Spack](https://spack.io/) - A flexible package manager that supports multiple versions, configurations, platforms, and compilers.
 
 ## ChatOps