Use docker image for deploying Precaution

[MVrachev]

Is your feature request related to a problem? Please describe.
It's really frustrating when you try to setup Golang and our Golang dependencies on Heroku.
Even if we manage to use the Heroku go buildpack again there are difficulties because golang is not on Heroku after finishing of the deployment.
That, combined with the fact that Gosec uses a new Golang parser in version 2.0.0 which requires Golang installed, creates a lot of troubles.

We need a new solution for how we are going to deploy to Heroku.

Describe the solution you'd like
Docker image sounds like a reasonable solution.
This will give us the freedom to deploy everywhere and customize our build for our needs.
Another bonus is that it will really useful for our future contributors.

[joshuagl]

Having a container image will likely make a switch to Circle CI easier too #226