2021-04-14 Masaya Tojo Version up. * configure.ac (AC_INIT): Verson up from `1.0.0` to `1.0.1`. * guix.scm (extract-green-color)[version]: Verson up from `1.0.0` to `1.0.1`. Update ChangeLog. * ChangeLog: Add logs. Add `Install from the source' section. * README.md[Install from the source]: New section. Add ChangeLog file. * ChangeLog: New file. Edit `README.md` file. * README.md: Rename title from `extract-green-color` to `Extract-green-color`. [Requirements]: New section. [Installation]: New section. [Usage]: New section. [License]: New section. Initial commit.