Added primary-colum to page_tag, formatted sql queries

tables.sql

@@ -45,6 +45,7 @@ CREATE TABLE tag (
 CREATE TABLE page_tag (
   `page_id` CHAR(16) NOT NULL,
   `tag_id`  CHAR(16) NOT NULL,
+  `primary` BOOLEAN NOT NULL,
 
   PRIMARY KEY (`page_id`, `tag_id`),
   FOREIGN KEY (`page_id`) REFERENCES page(`id`) ON DELETE CASCADE,