Platforming - moving up sloped surfaces ?

I am trying to script a first person controller.

I currently have vectors for velocity and gravity and apply each vector to the controller object in Update, when the object collides with a surface it will set these vectors to 0 making it stop. When the object exits the collision it will re-set the vectors.

This works fine on level surfaces but how do I get it to work with sloped surfaces ?

Is there any way when I move forward I can move up the surface, obviously at an angle.

I think I need to rotate the object to match the surface it is on but I don't know how to do this.

Any help is appreciated. Thanks.