Add a rake task to create demo data

Useful for development, review apps and our demo instance

lib/tasks/data_demo.rake

@@ -0,0 +1,8 @@
+namespace :data do
+  desc 'Create demo data using our factories'
+  task demo: :environment do
+    include FactoryGirl::Syntax::Methods
+    create(:full_conference)
+    create(:admin, email: 'admin@osem.io', username: 'admin', password: 'password', password_confirmation: 'password')
+  end
+end