add .gitignore file (#18)

* add shellcheck

* edit shellcheck

* edit shellcheck

* add Git Guardian workflow

* Sync the master and dev branches (#16)

* edit shellcheck (#8)

* add shellcheck

* edit shellcheck

* edit shellcheck

* Update README.md (#9)

* Update README.md (#10)

* Update README.md (#11)

* Update README.md (#12)

* add Git Guardian workflow (#13)

* add shellcheck

* edit shellcheck

* edit shellcheck

* add Git Guardian workflow

* Update README.md (#14)

* Update README.md (#15)

* edit release badge

* add .gitignore file