feat: add carryforward option to config

[mrexox]

:zap: Summary

Add carryforward option to YAML config. Also add a note about all value.

:ballot_box_with_check: Checklist

• [ ] Add specs

[coveralls-official[bot]]

Pull Request Test Coverage Report for Build 5025328501

• 2 of 2 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.01%) to 90.613%

---

Totals
Change from base Build 5012768357:	0.01%
Covered Lines:	724
Relevant Lines:	799

---

💛 - Coveralls