Add in functionality for dashboard page buttons

[zgarada]

Changes:

• dashboard.html: fixed buttons to route to corresponding links
• leaderboard.html: fixed minor error

Things to note:

• User lesson progression/quiz progression are not being tracked by the database, so we are currently sending in fixed course_id for the lesson reference and fixed lesson_id for the quiz reference.
• Daily challenge currently not created, so i set up a temporary route that displays a message.

[alexchen2]

Hey Zain, just wanted to give you a heads up that one of my currently-open PRs (#145) already addresses all but one of these changes, alongside fixing numerous other functional bugs and hooking up pages together (e.g. quizzes actually update points on dashboard and leaderboard, all users show up on the leaderboard ranked, dashboard spacing isn't wonky anymore, etc.).

The only thing that I didn't catch was the daily challenge button route, but I feel like returning an empty page with a single string isn't very user-friendly and would make the final demo product feel extremely unpolished. Maybe a suggestion would be to just hook up the button tag with an onclick= attribute, which triggers an JS alert function to print a message on the same page (maybe a "This feature will be implemented in the future"-type of message)?

[zgarada]

Hey Alex, i see your PR covers most of the changes that I made so to avoid any merge conflicts, I suggest that we just don't merge my PR and you can add that onlick attribute to the daily challenge button. If you suggest otherwise, let me know. Thanks.