Make sorting and attachments work

app/models/product.rb

@@ -45,9 +45,28 @@ class Product
     url: '/system/product/:id/images/:style.:extension',
     styles: {medium: '512x512>', thumb: '128x128>', large: '896x896>', small: '320x320>'},
     default_url: '/assets/user/blank-pixel.png'
-  validates_attachment :image, content_type: {content_type: ["image/jpg", "image/jpeg", "image/png", "image/gif"]}
+  #validates_attachment :image, content_type: {content_type: ["image/jpg", "image/jpeg", "image/png", "image/gif"]}
+  #validates_attachment :image, allow_nil: true
+  validates_attachment_content_type :image, content_type: %w(image/jpeg image/jpg image/png)
 
 
+  def self.ensure_correct_position_values!
+    # structured woud be: {supplier1: {category1: [p1, p2, p3], category2: [p1, p2]}, supplier2: {category1: [p1], ...}}
+    structured = Product.all.inject({}) do |aggregate, p|
+      aggregate[p.supplier_id] ||= {}
+      aggregate[p.supplier_id][p.product_category_id] ||= []
+      aggregate[p.supplier_id][p.product_category_id] << p
+      aggregate
+    end
+
+    structured.each do |(supplier_id, product_categories)|
+      product_categories.each do |(product_category_id, products)|
+        products.sort_by{_1.position.to_i}.each.with_index { |product, position| product.update position: position }
+      end
+    end
+    structured
+  end
+
 #private
 
   #def persist_product_category_ids