Github webhook fails to detect branch deletions

Github sends a push event which represents a branch deletion. We interpret it incorrectly as a branch update/create. This is part of the JSON data:

{
  "ref": "refs/heads/carles/354-pull-requests",
  "before": "0732e6cb8ef11e7f1236c5cf6ff05d11651c1a7f",
  "after": "0000000000000000000000000000000000000000",
  "created": false,
  "deleted": true,
  "forced": true,
  "base_ref": null,
  "compare": "https://github.com/pretenders/ployst/compare/0732e6cb8ef1...000000000000",
  "commits": [

  ],
  "head_commit": null,
  ...

pretenders / ployst

Github webhook fails to detect branch deletions #105