kryzet/git-submit50

AI Summary: Create a shell script that uses git to submit CS50 problem sets. The script must fetch a .gitignore template from a URL, ensure all necessary files for submission are present (and not ignored), and then proceed with the git submission. Failure to find required files should result in an error.

AI Summary: Improve the shell script for submitting CS50 problems to handle SSH key absence more gracefully. The script currently attempts an HTTP push regardless of the reason for SSH push failure. The task requires modifying the script to specifically check for SSH key errors before resorting to the HTTP fallback.

AI Summary: Implement year verification in a `git-submit50` shell script to ensure that the submission slug contains the correct course year, mirroring the functionality of `submit50`. This involves checking the slug against the expected year and rejecting submissions with incorrect years.

AI Summary: Determine the shebang compatibility of a shell script on OS X and provide a corrected shebang line if necessary to ensure the script functions correctly on OS X systems. This involves testing the existing shebang and potentially modifying it to use a compatible interpreter.