FEATURE: further restrict downloading of backups

- send email to logged in admin when they press the "download" button
- show pop-up that email was sent
- create email template
- require a valid token to download backup

lib/email_backup_token.rb

@@ -0,0 +1,28 @@
+class EmailBackupToken
+
+  def self.key(user_id)
+    "email-backup-token:#{user_id}"
+  end
+
+  def self.generate
+    SecureRandom.hex
+  end
+
+  def self.set(user_id)
+    token = self.generate
+    $redis.setex self.key(user_id), 1.day.to_i, token
+    token
+  end
+
+  def self.get(user_id)
+    $redis.get self.key(user_id)
+  end
+
+  def self.del(user_id)
+    $redis.del self.key(user_id)
+  end
+
+  def self.compare(user_id, token)
+    token == self.get(user_id)
+  end
+end