Create a "netpyne" command to run models using the new format i.e. > netpyne index.npjson

[salvadord]

Currently it is not clear how users should run models using the new format. As previously discussed, we should take advantage of the index file and create a command netpyne that can be executed from the command line and takes care of compiling the mod files and running the init.py file based on the paths specified in the index file.

the user would just need to go into the model root folder and run: netpyne index.npjson

[pgleeson]

Here is ann example of how we make command line scripts in pyneuroml:
https://github.com/NeuroML/pyNeuroML/blob/master/setup.cfg#L42-L44