rails engine - vendor/bundle and vendor/cache

[jsnark]

I created two rails engines.  In one of them 'bundle install' generated only a vendor/cache directory.  In the other one, 'bundle install' created both vendor/cache and vendor/bundle.  The vendor/bundle directory is causing me some problems.  I do not remember what I did differently when creating the two engines.

What causes 'bundle install' to create the vendor/bundle directory and how do I avoid this?

Thanks in advance.

[jsnark]

Found the solution.  This explanation may not be 100% accurate.

Bundle remembers how it was first executed in the directory '.bundle'.  Subsequent executions use this information.  'bundle install' puts the gems in the vendor/bundle directory.  'bundle package' puts the gems in the vendor/cache directory.

Apparently in the first engine I ran 'bundle package' first and in the second I ran 'bundle install' first.  To fix the problem, I deleted the vendor/bundle, vendor/cache, and .bundle directories and then ran 'bundle package', recreating the vendor/cache directory but not the vendor/bundle directory.