Add appeals (#17364)

* Add appeals

* Add ability to reject appeals and ability to browse pending appeals in admin UI

* Add strikes to account page in settings

* Various fixes and improvements

- Add separate notification setting for appeals, separate from reports
- Fix style of links in report/strike header
- Change approving an appeal to not restore statuses (due to federation complexities)
- Change style of successfully appealed strikes on account settings page
- Change account settings page to only show unappealed or recently appealed strikes

* Change appealed_at to overruled_at

* Fix missing method error

app/models/appeal.rb

@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: appeals
+#
+#  id                     :bigint(8)        not null, primary key
+#  account_id             :bigint(8)        not null
+#  account_warning_id     :bigint(8)        not null
+#  text                   :text             default(""), not null
+#  approved_at            :datetime
+#  approved_by_account_id :bigint(8)
+#  rejected_at            :datetime
+#  rejected_by_account_id :bigint(8)
+#  created_at             :datetime         not null
+#  updated_at             :datetime         not null
+#
+class Appeal < ApplicationRecord
+  belongs_to :account
+  belongs_to :strike, class_name: 'AccountWarning', foreign_key: 'account_warning_id'
+  belongs_to :approved_by_account, class_name: 'Account', optional: true
+  belongs_to :rejected_by_account, class_name: 'Account', optional: true
+
+  validates :text, presence: true, length: { maximum: 2_000 }
+  validates :account_warning_id, uniqueness: true
+
+  validate :validate_time_frame, on: :create
+
+  scope :approved, -> { where.not(approved_at: nil) }
+  scope :rejected, -> { where.not(rejected_at: nil) }
+  scope :pending, -> { where(approved_at: nil, rejected_at: nil) }
+
+  def pending?
+    !approved? && !rejected?
+  end
+
+  def approved?
+    approved_at.present?
+  end
+
+  def rejected?
+    rejected_at.present?
+  end
+
+  def approve!(current_account)
+    update!(approved_at: Time.now.utc, approved_by_account: current_account)
+  end
+
+  def reject!(current_account)
+    update!(rejected_at: Time.now.utc, rejected_by_account: current_account)
+  end
+
+  private
+
+  def validate_time_frame
+    errors.add(:base, I18n.t('strikes.errors.too_late')) if Time.now.utc > (strike.created_at + 20.days)
+  end
+end