Add surveys; custom generated by admins

Available during registration or after conference

Co-authored-by: Shyukri <shshyukriev@suse.com>
Co-authored-by: Henne <hvogel@opensuse.org>
Co-authored-by: Moises <mdeniz@suse.com>

db/migrate/20160630130731_create_survey_submissions.rb

@@ -0,0 +1,10 @@
+class CreateSurveySubmissions < ActiveRecord::Migration
+  def change
+    create_table :survey_submissions do |t|
+      t.integer :user_id
+      t.integer :survey_id
+
+      t.timestamps null: false
+    end
+  end
+end