It doesn't make sense to have mailman-bundler install a development environment.
By default it's setup using released packages from pypi and not git. There were a couple of people who were/are interested in contributing in gsoc that set everything up and then asked how they could start contributing. They were then told, that they needed the actual git repos and should install everything by hand and not use mailman-bundler.
People who are interested in developing should not be instructed to use mailman-bundler in the first place. Instead they should refer to the documentation on readthedocs.org.
Another issue with mailman-bundler is that the settings are currently kept up to date with the master branches of hyperkitty and postorius. The instructions to clone the repository won't work because the released projects can be (and currently are) incompatible with the git repo. People should use a released version of mailman-bundler instead. Additionally mailman-bundler should pin the versions of hyperkitty and postorius so no incompatibilities can occur when an old mailman-bundler is used to get newer versions of hyperkitty and postorius.
To sum things up:
- Drop dev environment
- Adapt docs to instruct people to use released versions of mailman-bundler
- Pin versions of hyperkitty and postorius