Bump Jekyll from 3.8.4 to 4.2.0

Improve language inclusiveness in Part 2 (#45)

Update gems

Replace rake commands with rails

Merge pull request #42 from brug-be/improve-big-picture-flow

Applying changes suggested in PR.

clarify where to type rails server, lets call the app rg-blog

Fix typos, flow, consistency

Added bit.ly link to the RG BXL guide.

Increase consistency. And remove some heavy word repetition.

re-integrate the later topics with the new structure.

Rewrite of part 1 of part 2 nearly makes sense like that

Some inital idea on how to restructure part 2 of the guide .. end is still untouched.

Tiny improvement on reading flow

Merge pull request #38 from brug-be/fix-github-repo-links