[Command] Added LockHelper

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | yes https://github.com/symfony/symfony/pull/10475
| Applies to    | Symfony version 2.6+
| Fixed tickets | -
You're saying "hosts", which makes me think of host names, not actual machines. What about saying:

>
The lock handler only works if you're using just one server. If you have several servers...

... I may also be misinterpreting what you mean :).