Add new installation methods to the readme.
Double word.
 Merge branch 'link-to-new-installation-methods' into 'master'

Link To New Installation Methods
Fix notification specs

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Merge branch 'master' of dev.gitlab.org:gitlab/gitlabhq
Merge branch 'master' of github.com:gitlabhq/gitlabhq