Implement mail aliases

migrations/20231008140942_alias.sql

@@ -0,0 +1,7 @@
+-- Add migration script here
+CREATE TABLE alias (
+	alias TEXT NOT NULL PRIMARY KEY,
+	type mail_type NOT NULL CHECK (type = 'alias'),
+	dest TEXT NOT NULL REFERENCES emails(mail),
+	FOREIGN KEY (alias, type) REFERENCES emails (mail, type)
+);