Add support for EBS (closes #128)

[jbeemster]

This PR adds the ability to attach EBS configuration options to instance groups which should allow the use of EBS only instance types such as m4 and c4.

[alexanderdean]

Any idea what is causing the Travis failures @jbeemster?

[jbeemster]

It's a version bump in a dependency not related to this PR. It passes on any version over Ruby 2.2.

[alexanderdean]

Morning @rslifka ! Any chance of getting this merged before the holidays? Having to choose between c3s with no disk or i2s with no CPU is killing us at Snowplow right now...

[rslifka]

Hello @alexanderdean! I think you mean @robert2d :)

It looks like it's failing when the dependency pulls in the latest activesupport. My laptop died and am awaiting replacement - no development environment :(

[robert2d]

We might need to lock the activesupport version back to be compatible with ruby ~2.0. Otherwise it might be time to leave them behind and drop support for older rubies. Im in favour of attempting to support anything >= 2.0 But that said i'm flat out till post Xmas. I'll try and get to this tomorrow though

[alexanderdean]

Awesome - thanks @robert2d ! Appreciate it.

[rslifka]

Alright, we can definitely drop 2.0.

Then, maintenance of Ruby 2.0.0 will be ended at Feb. 24th, 2016.

[rslifka]

There is no stated EOL date for 2.1 that I can find apart from a mention on ruby-lang.org that it will EOL "soon" as it has been in security mode since March 2016, which means folks on 2.1 have had nine months to adjust. 2.2 was released 12/2014, which has given folks two years to make the switch from <= 2.1 to 2.2.

Stepping back... if 2.1 is a huge problem to support, then we need to consider our ability to support the people using this given our limited resources, and being vocal about support here on GitHub. Since 2012 I have made the decision to support as much as possible without significant personal cost.

I am in favour of dropping 2.0 and 2.1 support.

If someone on 2.1 or earlier wants to contribute the ability for older versions to be supported, then by all means :)

[robert2d]

Im just pushing a branch now which disables testing on travis for 2.0 and 2.1. I'll merge post tests passing, then rebuild this pull request.

[alexanderdean]

Amazing, thanks both!

[robert2d]

Going to merge this in now and then run a manual build on travis

[robert2d]

Its in the wild guys: https://rubygems.org/gems/elasticity/versions/6.0.9 hope that helps you relax before Xmas @alexanderdean

[alexanderdean]

Thanks so much @robert2d !