Elgg Plugin show "404" not found

I am trying to develop a new plugin called "Group Reviews". I used the source code of discussion plugin as base and have created my plugin on that. I can see the plugin URL is added to the sidebar menu of the group but when I click on it. It shows me the "404 Page not found error".

My error_log also does not have any log to track the issue.

Anyone please help! Just tell me where I am going wrong and I will do the rest.

Here is the source code of the plugin: https://github.com/rohit1290/group_review