Added CSV export for items

app/controllers/items_controller.rb

@@ -4,6 +4,19 @@ class ItemsController < ApplicationController
   # GET /items or /items.json
   def index
     @items = Item.all.includes(:category, :user, :room).order(created_at: :desc)
+
+    respond_to do |format|
+    format.html # Rendert ganz normal deine Bestandsliste im Browser
+    format.csv do
+      # Dateiname generieren, z.B. "inventar_export_2026-05-22.csv"
+      filename = "inventar_export_#{Time.current.strftime('%Y-%m-%d')}.csv"
+
+      # Daten generieren und als Download an den Browser senden
+      send_data Item.to_csv,
+                filename: filename,
+                type: "text/csv; charset=utf-8; header=present"
+      end
+    end
   end
 
   # GET /items/1 or /items/1.json