Create the backend logic for isResolved by adding an attribute to a topic

[LujainAlMansoori]

Description: This involves connecting the "Urgent" button in the front-end to the isUrgent attribute in the backend, specifically to the topic object.

Estimated effort: This effort would be easy since the existing infrastructure for the topic already exists.

Dependencies: This issue has no dependencies.

Acceptance criteria: The topic object needs to have an isUrgent attribute included in it, this has to be reflected in the /api (when we showcase the topic object in the api to check the return objects of all the database). There also needs to be automated testing to ensure the attribute is in the backend and exists as a topic's variable

[mbfannan]

Resolved by pull request #72 .