Deploy to heroku buttons broken

[timwis]

Hi all 👋🏻 long time no see. I've had some reports from users of JKAN that the authentication isn't working. Upon investigation, it looks like the issue is that our gatekeeper "Deploy to Heroku" button was deploying the development branch, and that branch isn't working (see #64).

I'm assuming the default branch used to be master, and at some point it switched to development, after work on the new version began.

The heroku button code snippet tends to leave out the branch, e.g.:

<a href="https://heroku.com/deploy?template=https://github.com/prose/gatekeeper">
  <img src="https://www.herokucdn.com/deploy/button.svg" alt="Deploy">
</a>

So it uses the default git branch. When the default branch changed to development (or when the development branch stopped working), any instances deployed via a button like this after that point would not have worked (not sure when that was).

For now, you can resolve this issue by appending the branch name to the button snippet, e.g.:

<a href="https://heroku.com/deploy?template=https://github.com/prose/gatekeeper/tree/master">
  <img src="https://www.herokucdn.com/deploy/button.svg" alt="Deploy">
</a>

But if there are a lot of "Deploy to Heroku" buttons out there without the explicit branch name, I'd recommend changing the default branch back to master, or getting the development branch into a state that works on a fresh Heroku deploy.