Don't attempt to call chomp on nil if Git is not installed.
Add test for missing git when generating posts.
Don't show errors if `git config` fails.
Merge pull request #14 from myfreecomm/master

* pr/14:
  Don't show errors if `git config` fails.
  Add test for missing git when generating posts.
  Don't attempt to call chomp on nil if Git is not installed.