alias

also remove id since it's not useful for mailbox case (not like
mailbox can be renamed and we need a fixed it)

migrations/schema.sql

@@ -120,9 +120,8 @@ CREATE TABLE IF NOT EXISTS eventlog(
     PRIMARY KEY (id));
 
 CREATE TABLE IF NOT EXISTS mailboxes(
-    id VARCHAR(128) NOT NULL,
-    name VARCHAR(128) NOT NULL UNIQUE,
-    aliasTarget VARCHAR(128), /* the target if type is an alias */
+    name VARCHAR(128) NOT NULL,
+    aliasTarget VARCHAR(128), /* the target name type is an alias */
     creationTime TIMESTAMP,
 
     PRIMARY KEY (id));