Link to newer Docker image in the readme

[lukechilds]

I created my own Docker image (lukechilds/electrumx) due to some issues I had with the current image recommended in the readme (followtheart/electrumx).

The followtheart image doesn't follow Docker best practices and is also quite large and out of date. I believe my image is better because:

Size

lukechilds/electrumx: 40MB
followtheart/electrumx: 175MB

Follows Docker conventions

• All settings are passed in as ENV vars (no need for ENV folder)
• Runs ElectrumX directly as PID 1 instead of bash -> daemon
  • Interactive Docker sessions attach directly meaning Control-C works
  • Interactive Docker sessions get ElectrumX output to STDOUT
  • ElectrumX output will be piped to normal Docker logging tools
  • You shouldn't dockerize a daemon, the Docker image itself should be daemonized
• Reproducible builds: separate branch for each release (followtheart container builds current master)

Up to date

Pulling from Docker Hub will pull the latest ElectrumX release. You can also specify a tag to pull specific older ElectrumX releases.

The latest followtheart build on Docker Hub is 6 months out of date.

Secure

If no SSL cert is provided one will be automatically generated on first boot.

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Following these rules makes the image much easier to orchestrate in other Docker projects (e.g Dockerized Vertcoin Electrum Server), it's also currently the most used ElectrumX image on Docker Hub.

Let me know if you'd like to link to this image instead and I'll happily submit a PR.

[kyuupichan]

As I don't user Docker and @followtheart initially added this to the repo, I'd his/her thoughts.

Yes a PR would be nice. Please mention in the commit log it closes this issue.

[lukechilds]

Of course, opened a PR.