Write some software

I need you to develop some software for me. I would like this software to be developed for Linux using PHP. Develop a plugin for roundcube 1.3.4 that allows a user to login with the following url: [login to view URL] If a user was previously logged in the browser, he should be automatically logged out and the new user should be logged in instead. When the browser tab is closed, the user should automatically be logged out, even if the entire browser is not shutdown.