Implements echo-ruby

[web3melk]

This PR implements the echo example in Ruby

[tuler]

Thank you for the contribution!

There are two important characteristics in the build of a dapp, in any language.

1. reproducibility
2. small images

To improve on number 1 I suggest using bundler, and committing a Gemfile and Gemfile.lock
To improve on number 2 I suggest using a multi-stage build, where stage 1 uses an image that contains ruby-dev and build-essential, and uses bundler with a local path. On stage 2 you use a slimmer runtime image and copy build results from stage 1.

[tuler]

Nice! I'm not a ruby guy, but it looks good. I'll defer to others for final review.

In the meantime I'd like to invite you to review a Ruby template for sunodo.
sunodo/sunodo-templates#12

To test it, install sunodo (brew install sunodo/tap/sunodo), then run sunodo build from the template directory.
It will build the machine, then sunodo run will run a node for the application.
I tested it and it worked fine.

[web3melk]

Hi @tuler
Did you create the template based on my code?

[tuler]

Hi @tuler
Did you create the template based on my code?

The template is in the link above. It’s not an echo application, just the loop of fetching inputs, and a Dockerfile compatible with sunodo build system.