Added quantity filtering by domain

app/models/ingredient.rb

@@ -41,7 +41,7 @@ class Ingredient < ActiveRecord::Base
     self.toggle!(:hidden)
   end
 
-  def self.filter(project, filters = {}, requested_q = Quantity.none)
+  def self.filter(project, filters, requested_q = Quantity.none)
     ingredients = all
 
     if filters[:name].present?

app/models/quantity.rb

@@ -34,4 +34,14 @@ class Quantity < ActiveRecord::Base
   def calculate(inputs)
     Formula.new(self.project, self.formula).calculate(inputs)
   end
+
+  def self.filter(project, filters)
+    quantities = all
+
+    if filters[:domain].present?
+      quantities = quantities.where(domain: domains[filters[:domain]])
+    end
+
+    quantities
+  end
 end