Make --git-dir work with home folder reference ~

Signed-off-by: Jacob Stopak <jacob@initialcommit.io>

Author: initialcommit-io

git_dummy/__main__.py

@@ -24,7 +24,7 @@ def main(
     ),
 ):
     settings.name = name
-    settings.git_dir = os.path.join(git_dir, name)
+    settings.git_dir = os.path.join(os.path.expanduser(git_dir), name)
     settings.commits = commits
 
     repo = git.Repo.init(settings.git_dir)