Make ingredient editor form_field_id unique

Before the ID was not unique producing duplicated DOM ids for multiple instances
of the same element type on the same page.

Since we want to be able to access the input via JS
we need to have a unique DOM ID.

app/decorators/alchemy/ingredient_editor.rb

@@ -64,8 +64,12 @@ def form_field_name(column = "value")
       "element[ingredients_attributes][#{form_field_counter}][#{column}]"
     end
 
+    # Returns a unique string to be passed to a form field id.
+    #
+    # @param column [String] A Ingredient column_name. Default is 'value'
+    #
     def form_field_id(column = "value")
-      "element_ingredients_attributes_#{form_field_counter}_#{column}"
+      "element_#{element.id}_ingredient_#{id}_#{column}"
     end
 
     # Fixes Rails partial renderer calling to_model on the object

spec/decorators/alchemy/ingredient_editor_spec.rb

@@ -67,12 +67,12 @@
 
   describe "#form_field_id" do
     it "returns a id value for form fields with ingredient as default" do
-      expect(ingredient_editor.form_field_id).to eq("element_ingredients_attributes_0_value")
+      expect(ingredient_editor.form_field_id).to eq("element_#{element.id}_ingredient_#{ingredient.id}_value")
     end
 
     context "with a value given" do
       it "returns a id value for form fields for that column" do
-        expect(ingredient_editor.form_field_id(:link_title)).to eq("element_ingredients_attributes_0_link_title")
+        expect(ingredient_editor.form_field_id(:link_title)).to eq("element_#{element.id}_ingredient_#{ingredient.id}_link_title")
       end
     end
   end