Fix toggle of shared badges.

The earned badges controller was passing the `earned_badge_id` to the
update query which as expecting a `badge_id`.

Closes #482.
Updated kapital controls
Use join for badges on student dashboard.

Use an ActiveRecord join to select the badges for the student dashboard.
This makes a single trip to to the database to obtain all of the records
necessary to display the badges table of the student dashboard. No
longer using the momoization within badges, so it may not be necessary
if it is not used elsewhere.

Closes #477.
Unify assignments queries in student dashboard.

Unify assignments queries in the student dashboard. Memoize the group by
assignment type that is performed three times.

Closes #485.
Remove unused properties from student dashboard.

Remove unused controller object properties from the student dashboard
controller.

Closes #486.
Merge pull request #483 from bellotastudios/toggle

Fix toggle of shared badges.
Display both raw and unmultiplied scores while the window is open
Move users/scores to students/scores
Updated display of raw and multiplied scores
Merge pull request #487 from bellotastudios/badges

Use join for badges on student dashboard.
Merge pull request #490 from bellotastudios/weights

Weights
Merge pull request #491 from bellotastudios/assignments

Unify assignments queries in student dashboard.
Showing multiplied grades
Merge pull request #492 from bellotastudios/performance

Remove unused properties from student dashboard.
Merge pull request #494 from bellotastudios/weights-again

Showing multiplied grades
Update GSI dashboard with performance gains.

Updated the GSI dashboard for the student dashboard performance gains.
Components of the GSI dashboard had broken because the student dashboard
had renamed the controller variables and methods.

See #491.
Merge pull request #495 from bellotastudios/performance

Update GSI dashboard with performance gains.
Fix grade distro display for student views
Merge pull request #496 from bellotastudios/gradedistro

Fix grade distro display for student views
Display student sidebar on challenges