structure updates index.md

[dvorakvlad]

Structure updates in index.md
Needs grammatic changes

• I have read freeCodeCamp's contribution guidelines.
• My pull request has a descriptive title (not a vague title like Update index.md)
• My pull request targets the master branch of freeCodeCamp.
• None of my changes are plagiarized from another source without proper attribution.
• My article does not contain shortened URLs or affiliate links.

If your pull request closes a GitHub issue, replace the XXXXX below with the issue number.

Closes #XXXXX

[RandellDawson]

Closed and Reopened this PR to attempt to resolve a specific Travis build failure.

[greggubarev]

LGTM 👍 🎯

Thank you for the PR ✨ 🎉
We're happy to accept these changes and look forward to your future contributions 👏

Happy coding!