user model: added enabled column

setup/sqlite.sql

@@ -1,6 +1,6 @@
 CREATE TABLE page(id INTEGER PRIMARY KEY, name varchar(256), lastrevision integer, visible integer DEFAULT 1);
 CREATE TABLE user(id INTEGER PRIMARY KEY,username varchar(64), 
-password blob, salt blob, permissions integer);
+password blob, salt blob, permissions integer, enabled integer DEFAULT 1);
 CREATE TABLE session(id INTEGER PRIMARY KEY, csrf_token varchar(32), 
 creationtime date, userid integer , token varchar(32));
 CREATE TABLE permissions(id INTEGER PRIMARY KEY, permissions integer,