Feat: Add support for variables #16

[sgtcortez]

Closes: #16 .

Task list

This pull request is well tested, and does not break the current code.

• [x] Works on both operating system.
• [x] Is well tested.
• [x] Is documented. Readme, Changelog, binary help output and etc ...

Description of the feature

• [x] Is backward compatible?
• [x] Is the commit history well described?