adding more verbository about installing module software

Signed-off-by: vsoch <[email protected]>

Author: vsoch

README.md

@@ -16,17 +16,14 @@ And container technologies:
  - [Podman](https://podman.io)
  - [Docker](https://docker.io)
 
-Coming soon:
-
- - [Shifter](https://github.com/NERSC/shifter)
 
 You can use shpc if you are:
 
 1. a linux administrator wanting to manage containers as modules for your cluster
 2. a cluster user that wants to maintain your own folder of custom modules
 3. a cluster user that simply wants to pull Singularity images as GitHub packages.
 
-These use cases will be better flushed out and documented as the library is developed.
+A module technology is required in all cases.
 
 📖️ Read the [documentation](https://singularity-hpc.readthedocs.io/en/latest/) 📖️
 ⭐️ Browse the [container module collection](https://singularityhub.github.io/singularity-hpc/) ⭐️

docs/getting_started/installation.rst

@@ -4,8 +4,11 @@
 Installation
 ============
 
-Singularity Registry HPC (shpc) can be installed from pypi, or from source. For either, it's
-recommended that you create a virtual environment, if you have not already
+Singularity Registry HPC (shpc) can be installed from pypi, or from source. 
+In all cases, a module technology is required such as `lmod (install intstructions) <https://lmod.readthedocs.io/en/latest/030_installing.html>`_
+or `environment modules (install instructions) <https://modules.readthedocs.io/en/latest/INSTALL.html>`_.
+Having module software installed means that the ``module`` command should be on your path.
+Once you are ready to install shpc along your module software, it's recommended that you create a virtual environment, if you have not already
 done so.