install curl before trying to install docker

[staticfrost]

Instances where curl is required to install docker but curl isn't installed first.

This checks for the curl command if it isn't found it will install curl from apt.

[trevj]

@staticfrost Thanks for contributing to Outline!

So, a problem is that this script is meant to run on a wide variety of platforms. Detecting the system type and providing instructions for each is a place I'd rather not go: for one thing, we strive to make as few changes to the system as possible (the obvious exception is the Docker install script but that's designed to run on a wide variety of systems).

@fortuna I'd rather solve this by providing instructions in the manager for both curl and wget - WDYT? That's a straightforward change and I think basically every VM out there comes with one of those two pre-installed.

[staticfrost]

@trevj thanks for the feedback. So instead of installing curl it should check if it has curl or wget and use which one it detects to then do the docker download?

[trevj]

@staticfrost Actually I was just thinking of the server manager's "advanced setup" but that's a good idea, you're right: the script could suggest curl or wget for the Docker install based on what's present on the system. I think that would be very useful.

[fortuna]

As a minimal change, we should support at least wget, since the advanced install instructions already use it, so we could assume the user will have wget installed.

[trevj]

@staticfrost Please let us know if you still have time to work on this!

[staticfrost]

@trevj Sorry for the delay I'll make a new commit this weekend I've thought of a far easy way to achieve this.