digitalocean opensource dev developer sticker hacktoberfest first-pull-request-and-commit tshirts good-first-issue first-pull-request hacktoberfest-starter hacktoberfest-swag hacktoberfest2020 hacktoberfest-accepted hacktoberfest-event

python java open-source php sql math cpp open geometry probability regression combinatorics hacktoberfest number-theory first-pull-request good-first-pr first-contribution hacktoberfest-swag hacktoberfest-accepted hacktoberfest2021