Add default .gitignore to the $workdir repo

This commit adds a simple .gitignore file to the $workdir repository
(~root/puppetcode) that ignore Vim swap files.  This is to avoid
confusion or potential unexpected attempts to do syntax validation
against those files.
Better glob for gitignore
Merge pull request #324 from joshbeard/add_gitignore

Add default .gitignore to the $workdir repo