add post on launching hercules ci

[domenkozar]

• [ ] pick an image from https://unsplash.com/search/photos/pattern
• [ ] link sprint report to previous sprint
• [ ] proofread
• [ ] merge PR (will be picked up soon by @nixos_org Twitter automation!)
• [ ] verify link on https://cards-dev.twitter.com/validator
• [ ] publish on twitter/hercules_ci, nixos weekly

[domenkozar]

Yeah, I wanted to make it as personal as possible, to get rid of the company fence wall texts :) After all, we're still part of Nix community.

Couldn't find an image that's not cheesy, so maybe we just skip it this time?