Add administrative webhooks (#18510)

* Add administrative webhooks

* Fix error when webhook is deleted before delivery worker runs

app/models/webhook.rb

@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: webhooks
+#
+#  id         :bigint(8)        not null, primary key
+#  url        :string           not null
+#  events     :string           default([]), not null, is an Array
+#  secret     :string           default(""), not null
+#  enabled    :boolean          default(TRUE), not null
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#
+
+class Webhook < ApplicationRecord
+  EVENTS = %w(
+    account.created
+    report.created
+  ).freeze
+
+  scope :enabled, -> { where(enabled: true) }
+
+  validates :url, presence: true, url: true
+  validates :secret, presence: true, length: { minimum: 12 }
+  validates :events, presence: true
+
+  validate :validate_events
+
+  before_validation :strip_events
+  before_validation :generate_secret
+
+  def rotate_secret!
+    update!(secret: SecureRandom.hex(20))
+  end
+
+  def enable!
+    update!(enabled: true)
+  end
+
+  def disable!
+    update!(enabled: false)
+  end
+
+  private
+
+  def validate_events
+    errors.add(:events, :invalid) if events.any? { |e| !EVENTS.include?(e) }
+  end
+
+  def strip_events
+    self.events = events.map { |str| str.strip.presence }.compact if events.present?
+  end
+
+  def generate_secret
+    self.secret = SecureRandom.hex(20) if secret.blank?
+  end
+end