ruby on rails - link for adding something to the session -

Do I have a link that will add something in session hash? For example, if I have a link, then it is done when clicked:

  session [: items]  

I have to trigger a JS file for that action, so I can update the session when the user clicks the link.

OK, what did I do, if someone crosses the other, then I will call this line as my controller , For example, if we add something to our paraMedge, then it will be.

  session [: items]