mailbox activation, closes #52

docs/mailboxes.md

@@ -0,0 +1,25 @@
+# Mailboxes configuration
+
+## `POSTMOOGLE_MAILBOXES_RESERVED`
+
+Space separated list of reserved mailboxes, example:
+
+```bash
+export POSTMOOGLE_MAILBOXES_RESERVED=admin root postmaster
+```
+
+Nobody can create a mailbox from that list
+
+## `POSTMOOGLE_MAILBOXES_ACTIVATION`
+
+Type of activation flow:
+
+### `none` (default)
+
+If `POSTMOOGLE_MAILBOXES_ACTIVATION=none` mailbox will be just created as is, without any additional checks.
+
+### `notify`
+
+If `POSTMOOGLE_MAILBOXES_ACTIVATION=notify`, mailbox will be created as in `none` case **and** notification will be sent to one of the mailboxes managed by a postmoogle admin.
+
+To make it work, a postmoogle admin (or multiple admins) should either set `!pm adminroom` or create at least one mailbox.