Add Test for Ubuntu 16.04

[arBmind]

Now that @strfry fixed our Travis Build, we should add a Ubuntu 16.04 test.
We use this for quite a while in production, so it should not be too hard.

What holds us back:

• upstart is always used (replaced with systemd on 16.04)

[zealot128]

...another prob i encountered was, that ITedd enforces Ruby 2.1.7. That does not compile for a Ubuntu 18 shipped Openssl at least anymore:

ossl_cipher.c:18:69: error: invalid application of ‘sizeof’ to incomplete type ‘EVP_CIPHER_CTX {aka struct evp_cipher_ctx_st}’
     memset(DATA_PTR(obj) = (ctx) = ALLOC(EVP_CIPHER_CTX), 0, sizeof(EVP_CIPHER_CTX))

I suggest just adding another app. I am working on supporting HRfilter/Fahrrad-Filter. Maybe we can add more "apps" to the build matrix? How about a Redmine instance?

[arBmind]

Good idea!
We might also fork itedd and update it. Testing apps that are really used by us and known to us it even better.
We just have to pin to a known good version, so we do not fail if the app is broken.

A very basic Redmine might work. We might also move the rmagick from https://github.com/hicknhack-software/ansible-redmine to this role set.

Another idea would be to create a repository with a basic rails-test app. Just a standard rails blog example produced by some documented commands. Easy to recreate for new rails and ruby versions. And easy to add various gems or rails features. Maybe something like this already exists.

[zealot128]

That kind of examples will become outdated soon, too, I fear.
One could create the app on demand, like using Suspenders or App composer to generate an app that "always" has kind of latest stuff inside.

But that is kind of a tinker project for someone else on some kind of a hack event 😛

Adding any kind of (OS) projects that are (semi)actively developed by us or are very similar to our company's own deployments is nice, as it makes sure, that new PRs does not break our own deployments :)

Thus, I try to add Hrfilter/fahrradfilter this week and rework the travis-ci script to support apps via build matrix, specific ansible version and test that with ubuntu 18.

[arBmind]

Sounds good, go ahead!

[zealot128]

Unfortunately, running systemd services inside a Docker is not easy.

If somebody with experience in Docker and/or Systemd can join in and try to make a minimal Docker + run config, that e.g. installs & starts a Redis or PG or so, that'll be great.

Things I've tried are in this PR...

#87 (comment)