Hi, you can create new table in the database for this purpose.
Then create add page for this table in the PHPRunner. To assign record to the user set up one field asLookup wizard on the "Edit as" settings dialog on the Visual Editor tab nd point it to the users table. Then you can filter records on the page and show assigned records only using User can see and edit their own records only option on the Advanced security settings dialog on the Securitytab.