Extend Profile by adding categories

I want to add an option of choosing expert categories for profiles of users at the time of registration or after registration while updating user profile. These categories are defined by the site wide categories plugin which apply to content types like videos. I am looking for suggestions on best way to go about this.

I am comfortable in coding using php and have basic concepts of elgg plugins.

Thanks.

 

Beginning Developers

Beginning Developers

This space is for newcomers, who wish to build a new plugin or to customize an existing one to their liking