setup: sqlite: Add "parent" refere to "page"

setup/sqlite.sql

@@ -1,4 +1,4 @@
-CREATE TABLE page(id INTEGER PRIMARY KEY, name varchar(256), title varchar(1024), lastrevision integer, visible integer DEFAULT 1);
+CREATE TABLE page(id INTEGER PRIMARY KEY, name varchar(256), title varchar(1024), lastrevision integer, visible integer DEFAULT 1, parent integer REFERENCES page(id));
 CREATE TABLE user(id INTEGER PRIMARY KEY,username varchar(64), 
 password blob, salt blob, permissions integer, enabled integer DEFAULT 1);
 CREATE TABLE session(id INTEGER PRIMARY KEY, csrf_token varchar(32),