implement /setup and /admin

app/controllers/admin/users_controller.rb

@@ -0,0 +1,45 @@
+class Admin::UsersController < Admin::BaseController
+  before_action :set_user, only: [ :edit, :update, :destroy ]
+
+  def index
+    @users = User.order(created_at: :desc)
+    @users = @users.where(role: params[:role]) if params[:role].present?
+    @users = @users.where("email LIKE ?", "%#{params[:q]}%") if params[:q].present?
+  end
+
+  def edit
+  end
+
+  def update
+    if @user.update(user_params)
+      redirect_to admin_users_path, notice: "User updated successfully."
+    else
+      render :edit, status: :unprocessable_entity
+    end
+  end
+
+  def destroy
+    if @user == current_user
+      redirect_to admin_users_path, alert: "You cannot delete your own account."
+      return
+    end
+
+    if @user == User.first
+      redirect_to admin_users_path, alert: "Cannot delete the first admin user (system default contact)."
+      return
+    end
+
+    @user.destroy
+    redirect_to admin_users_path, notice: "User deleted successfully."
+  end
+
+  private
+
+  def set_user
+    @user = User.find(params[:id])
+  end
+
+  def user_params
+    params.require(:user).permit(:name, :email, :role, :primary_language)
+  end
+end