* You can distinguish connection among others with specific `application_name`

    ```sql
    SELECT application_name FROM pg_stat_activity;
    /*
        application_name
    ------------------------
    psql
    ActionCable-PID-42
    (2 rows)
    */
     ```

  * It's possible to customize connection identification with `id` option in `cable.yml`

    `ActionCable-PID-#{$$}` is the default value

  * Related tests refactoring

  * `ActionCable::Server#config.cable` is no mutated anymore inside Redis subscription adapter