Administrateur can be param the acknowledgement of delivery mail object and body.

db/migrate/20160830142653_create_mail_templates_table.rb

@@ -0,0 +1,11 @@
+class CreateMailTemplatesTable < ActiveRecord::Migration
+  def change
+    create_table :mail_templates do |t|
+      t.string :object
+      t.text :body
+      t.string :type
+    end
+
+    add_belongs_to :mail_templates, :procedure
+  end
+end