Fixed Issue #355 - Added Leaderboard link in Navbar

[neerajd007]

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Yes

Solves which issue ?

Fixes #355

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Added leaderboard link in navbar. Live link : https://neerajd007.github.io/Opencode-Collaborative-19/

Checklist

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• [x] Signed the code of conduct.

• [x] Have you added yourself to the participants.

• [x] Joined opencode zulip server.

[neerajd007]

@ananya-agrawal I have made the changes, Please review.