Added a model for list_item and wrote a test for it
Added the test for the list_item model

Accidentally forgot to add the test in the last commit. Here is the test I wrote for the model.
Revert "Added the test for the list_item model"

This reverts commit 9a7c7ed0821f11e63f41c18966928d14dd1ab22c.
Added a list items link and wrote a test for it

Added a list items link and wrote a test for it. Also fixed the issue with wrong css id.