[docs] PHP in Gitpod

[JesterOrNot]

See #383

[jankeromnes]

Fantastic PHP guide! Many thanks for writing it. 🙏

I've suggested a few minor improvements below.

[jankeromnes]

Maybe also mention how to start debugging below your example repo? E.g.:

Then simply open any .php file; open the Debug panel (crossed-out spider icon in the left vertical menu); and click on the green start button once. The debugger will automatically pause on the first line, allowing you to step through your code.

Also, there is something running on port 9000. I'm not sure what it is, but maybe you should onOpen: ignore it so that it doesn't open confusing notifications.

Also, why open in the internal Debug console? I find it a bit confusing, as it randomly won't open automatically, causing you to miss all the debug output sometimes. I personally prefer my Debugger to use an actual Terminal.

[JesterOrNot]

I find the official console to be more versatile as you can specify verbosity levels

[jankeromnes]

Looks good to me, many thanks! 🎉

Only a few small things. Please address them, and then feel free to merge this. 🙂

[jankeromnes]

Thanks for mentioning PECL! I didn't know we had that already.

It seems to me that PHP extensions are normally installed via apt-get (e.g. sudo apt-get install php-pgsql, as we currently do in our base Dockerfile), but I don't see the harm in mentioning it's available if you like to use that.