Added ingredient index and form

app/models/ingredient.rb

@@ -1,2 +1,13 @@
 class Ingredient < ActiveRecord::Base
+  enum group: {
+    meat: 0
+  }
+
+  belongs_to :project
+
+  validates :project, associated: true
+  validates :name, presence: true, uniqueness: {scope: :project_id}
+  validates :ref_amount, numericality: {greater_than: 0}
+  validates :ref_unit, presence: true, associated: true
+  validates :group, inclusion: {in: groups.keys}
 end