submit form without method name?

I have seen some sites that use something like app.com/controller-name
in forms and tell no method...how can i do this?

It is possible to setup routes to default to a certain action based on
incoming data. When you use a scaffold generator, for example, things
like POST for site.com/controller automatically go to the Edit
actions. Look into how to edit your routes.rb file for how to set this
up.