Added Ingredient/Nutrient initialization

app/controllers/ingredients_controller.rb

@@ -4,8 +4,9 @@ class IngredientsController < ApplicationController
   before_action :authorize
 
   def index
-    @ingredient = Ingredient.new
-    @ingredient.nutrients.build
+    @ingredient = Ingredient.new(project: @project)
+    # passing attr for after_initialize
+    @ingredient.nutrients.new(ingredient: @ingredient)
     @ingredients = @project.ingredients
   end
 

app/models/ingredient.rb

@@ -24,4 +24,12 @@ class Ingredient < ActiveRecord::Base
   validates :ref_amount, numericality: {greater_than: 0}
   validates :ref_unit, presence: true, associated: true
   validates :group, inclusion: {in: groups.keys}
+
+  after_initialize do
+    if new_record?
+      units = self.project.units
+      self.ref_unit ||= units.find_by(shortname: 'g') || units.first
+    end
+  end
+
 end

app/models/nutrient.rb

@@ -8,4 +8,10 @@ class Nutrient < ActiveRecord::Base
   validates :quantity, presence: true, associated: true, uniqueness: {scope: :ingredient_id}
   validates :amount, numericality: {greater_than: 0}
   validates :unit, presence: true, associated: true
+
+  after_initialize do
+    if new_record?
+      self.unit ||= self.ingredient.ref_unit
+    end
+  end
 end