Can't add script: The script is an editor script

Hi, i want to draw all the BoxColliders in the Scene while i'm creating it, so i created the script below to draw a box using the Gizmos utility.

 using UnityEngine;
 
 [ExecuteInEditMode]
 public class ShowCollider : MonoBehaviour
 {
 
     // The Collider itself
     private BoxCollider _collider;
 
     void Start()
     {
         _collider = GetComponent<BoxCollider>();
     }
 
     void OnDrawGizmos()
     {
         Gizmos.color = Color.blue;
         Gizmos.DrawCube(_collider.center,_collider.size);
     }
 
 }

The problem is that i can't add this script to any object because it is an "editor script". I'm a bit confused on how should i use an "editor script" because from the documentation it looks like you can add an "editor scripts" to gameobjects, there is a manual entry here where they add an "editor script" to an object to keep it oriented towards a certain direction.

My script is in the ./Asset/Editor folder.

So what am i doing wrong? My guess is that there is something wrong with the OnDrawGizmos function.