Webhooks helps you to trigger some actions on your server when an event
happens with you repositories.
HMAC SHA512 key: it is a string that will be used to sign the payload;
this way you can be sure that the server knows the secret and you can go on to
process the request. You can use any character you want: letters, digits and
any symbol.
The server will create a HMAC over the payload using SHA512 and will add
a HTTP header: X-RocketGit-Signature: <signature>. It is
recommended to verify it before parsing the body, for security reasons.
It is not generated for application/x-www-form-urlencoded encoding.