Move Impl to Db_git.Impl

Signed-off-by: John Else <john.else@citrix.com>
Add skeleton test binary

Signed-off-by: John Else <john.else@citrix.com>
Add a test case

Signed-off-by: John Else <john.else@citrix.com>
Run test with make test

Signed-off-by: John Else <john.else@citrix.com>
Merge pull request #3 from johnelse/tests

Add a test binary