Added Ingredients model

command: rails generate redmine_plugin_model body_tracking ingredient
name:string ref_unit:references ref_amount:decimal hidden:boolean
source:references group:integer

test/unit/ingredient_test.rb

@@ -0,0 +1,9 @@
+require File.expand_path('../../test_helper', __FILE__)
+
+class IngredientTest < ActiveSupport::TestCase
+
+  # Replace this with your real tests.
+  def test_truth
+    assert true
+  end
+end