Suggestion: Add gem env binpath that outputs all bin paths

[DannyBen]

After installing Ruby in some (all?) platforms or installation methods, there is a need to add the gem bin paths to the PATH variable.

Right now, the only way I found to obtain these bin paths, is with something like this:

gem env path | sed 's@[^:]\+@&/bin@g'

which appends /bin to each path in the gem env path output.

# I would love to be able to do this (or similar):
export PATH="$PATH:$(gem env binpath)"

# ...instead of this:
export PATH="$PATH:$(gem env path | sed 's@[^:]\+@&/bin@g')"