Add a slight rotation when moving horizontal

I have a movement script that I am using in a topdown style game. Currently I have the movements all working correctly except I am trying to add a slight rotation to my player object when moving in the horizontal direction. Here is what I have for the x,z movement:

 var x = Input.GetAxis("Horizontal") * Time.deltaTime;
 var z = Input.GetAxis("Vertical") * Time.deltaTime;
 var rotation = Input.GetAxis("Rotate") * Time.deltaTime;

 transform.Translate(x,0.0f,z);
 transform.Rotate(0.0f, rotation, 0.0f);

I also have a "Rotate" movement that rotates my object around the y-axis which could be why adding another rotation keeps messing up. Any ideas on how to add the slight rotation on horizontal movement?