use mode reference for rfid tags

app/models/rfid_tag.rb

@@ -1,3 +1,4 @@
 class RfidTag < ApplicationRecord
   belongs_to :user, required: false
+  belongs_to :mode, required: false
 end

db/migrate/20260729144217_update_rfid_tags_mode_from_string_to_mode.rb

@@ -0,0 +1,6 @@
+class UpdateRfidTagsModeFromStringToMode < ActiveRecord::Migration[8.0]
+  def change
+    remove_column :rfid_tags, :mode
+    add_reference :rfid_tags, :mode
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2026_03_19_181607) do
+ActiveRecord::Schema[8.0].define(version: 2026_07_29_144217) do
   create_table "active_storage_attachments", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -70,12 +70,13 @@ ActiveRecord::Schema[8.0].define(version: 2026_03_19_181607) do
 
   create_table "rfid_tags", force: :cascade do |t|
     t.string "identifier"
-    t.string "mode"
     t.datetime "created_at", default: -> { "CURRENT_DATE" }, null: false
     t.datetime "updated_at", default: -> { "CURRENT_DATE" }, null: false
     t.string "chip_id"
     t.integer "user_id"
+    t.integer "mode_id"
     t.index ["identifier"], name: "index_rfid_tags_on_identifier", unique: true
+    t.index ["mode_id"], name: "index_rfid_tags_on_mode_id"
     t.index ["user_id"], name: "index_rfid_tags_on_user_id"
   end