Moved Formula to separate model

db/migrate/001_create_schema.rb

@@ -11,7 +11,6 @@ class CreateSchema < ActiveRecord::Migration
       t.references :project
       t.integer :domain
       t.string :name
-      t.string :formula
       t.string :description
       # fields for awesome_nested_set
       t.references :parent
@@ -20,6 +19,13 @@ class CreateSchema < ActiveRecord::Migration
       t.timestamps null: false
     end
 
+    create_table :formulas do |t|
+      t.references :quantity
+      t.string :code
+      t.boolean :zero_nil
+      t.timestamps null: false
+    end
+
     create_table :column_views do |t|
       t.references :project
       t.string :name

db/migrate/002_load_defaults.rb

@@ -138,7 +138,7 @@ class LoadDefaults < ActiveRecord::Migration
         # Calculated quantities go at the and to make sure dependencies exist
         e2 = Quantity.create project: nil, domain: :diet, parent: e1, name: "Calculated",
           description: "Total energy calculated from macronutrients",
-          formula: "4*(Proteins || 0) + 9*(Fats || 0) + 4*(Carbohydrates || 0)"
+          formula_attributes: {code: "4*Proteins + 9*Fats + 4*Carbohydrates", zero_nil: true}
 
         Source.create project: nil, name: "nutrition label",
           description: "nutrition facts taken from package nutrition label"