When generating a new rails application (rails new) using a custom template that
includes gems from an authenticated source, the user has to provide credentials to
bundler.
One way to do this is by exporting environment variables, for example:
export BUNDLE_GITHUB__COM=user:pass: provides credentials for bundler to fetch
gems from github.com.
The problem this PR addresses is that we are currently scrubs all /BUNDLE_.*/
environment variables by wrapping our system calls in Bundler.with_clean_env.
We do this because we don't want our commands executed against the generated project
to use the generator's bundler environment (e.g. our gems): the generated project should
use it's own configuration.
The problem with Bundler.with_clean_env is that, on top of restoring environment
variables to their original state, it also scrubs any /BUNDLE_.*/ variables, which is harmful for authenticated gem sources.
This PR replaces Bundler.with_clean_env with Bundler.with_original_env, which only
restores environment variables to their initial state, without additional scrubbing.