Add Description of imgproxy-form repo and local-install

[mz-bmcqueen]

Folks with creds won't want to push their creds to the imgproxy-form out on the net. Add a section to the Readme describing how to clone that thing locally and use it. Or maybe just mention it so folks can easily swipe that code to put up their own url generators.

For ref:

https://github.com/progapandist/imgproxy-form

Easy task for the eager!

[vosmith]

This issue seems to be more appropriate for the imgproxy-form repository. Can we move it there and close this one?

[mz-bmcqueen]

It looked like the imgproxy-form repo was owned by some other project. It looks like these two belong together, and imgproxy-form might fight as an example UI in this project.

[vosmith]

Yes they are definitely related, but the change to the Readme seems like it should be done on the imgproxy-form project.

[DarthSim]

imgproxy-form is a kind of easy-test thing. Its goal is to give an ability to try your fresh deployment to Heroku without writing any code. Like press the button, fill the form, wow, it works! You totally shouldn't use it in production in any way. It's related only to the article, and I don't think we should mention it itself in the Readme.
On the other hand, it's absolutely safe. There is no communication between the form and any backend, even with your imgproxy instance. You can see this in its JS source.