fix deprections warnings
Backport upgrader script from GitLab

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Uppercase constants

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Merge branch 'fix/deprecations' of github.com:pgolm/gitlab-ci into pgolm-fix/deprecations

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Conflicts:
	config/initializers/secret_token.rb
 Merge branch 'pgolm-fix/deprecations' into 'master'

Fix deprecations

Ported from https://github.com/gitlabhq/gitlab-ci/pull/357
 Merge branch 'upgrader' into 'master'

Feature: Upgrade script