fix: issue where starter kit can only be run once

[mcorrello]

Changes:

• Fixes issue where starter kit can only be run once. More information is inside issue #29.
• Also checks if project name exists already in the current directory. If it does, stop running the starter kit with an error. Previously it was erroring out since the directory already existed.

Issue causing #29:
The cli file renames gitignore to .gitignore inside of /starter-kit. When the kit is run more than once, that file has already been renamed so it errors out.

Fix:
Check if gitignore exists without the dot. If it doesn't, don't rename the file since it doesn't need it.