Feature: display node modules in use at start

[typeoneerror]

pndev start

should show the currently used links:

find node_modules node_modules/\@* -depth 1 -type l -print | while read MODULE ; do
    echo "Linked module in use: $MODULE"
done

[christophermlne]

@typeoneerror i'd just add the ability to force install node_modules like this:

pndev start

IF yarn links in the @precision-nutrition folder detected:

"Linked module(s) in use: $MODULE". Use "pndev start -f" to overwrite linked modules.