complete adding destroy method

app/controllers/users_controller.rb

 class UsersController < ApplicationController
-  before_action :set_user, only: [:show, :edit, :update]
+  before_action :set_user, only: [:show, :edit, :update, :destroy]
   after_action :verify_authorized
 
   def index

app/policies/user_policy.rb

@@ -31,6 +31,6 @@ class UserPolicy < ApplicationPolicy
   end
 
   def destroy?
-    @current_user.admin_or_superadmin?
+    @current_user.admin_or_superadmin? && @current_user != @user
   end
 end

config/routes.rb

 Rails.application.routes.draw do
   devise_for :users
 
-  resources :users, except: :destroy
+  resources :users
   resources :clients
   resources :profiles, except: [:destroy, :index]