RealGud integration

[Pitometsu]

Check is RealGud able to find several python debuggers like ipdb in pipenv path.

[pwalsh]

pipenv.el now pushes the virtual env path to (exec-path) when a pipenv-managed project is activated, for example by (pipenv-activate).

• https://github.com/pwalsh/pipenv.el/blob/master/pipenv.el#L163
• https://github.com/pwalsh/pipenv.el/blob/master/pipenv.el#L327
• https://github.com/pwalsh/pipenv.el/blob/master/test/pipenv-test.el#L31

This should be enough for RealGud to find any executable it expects.

[Pitometsu]

Confirm, thank you.