Split DB Updates into seperate files, with the cutoff being 2.0.0

admin/database_updates/2.1.6.php

@@ -0,0 +1,27 @@
+<?php
+
+/*
+ * ITFlow - Database update to version 2.1.6 (from 2.1.5)
+ * Included by admin/database_updates.php - do not access directly
+ */
+
+defined('FROM_DB_UPDATER') || die("Direct file access is not allowed");
+
+    mysqli_query($mysqli, "CREATE TABLE `document_versions` (
+        `document_version_id` INT(11) NOT NULL AUTO_INCREMENT,
+        `document_version_name` VARCHAR(200) NOT NULL,
+        `document_version_description` TEXT DEFAULT NULL,
+        `document_version_content` LONGTEXT NOT NULL,
+        `document_version_created_by` INT(11) DEFAULT 0,
+        `document_version_created_at` DATETIME NOT NULL,
+        `document_version_document_id` INT(11) NOT NULL,
+        PRIMARY KEY (`document_version_id`)
+    )");
+
+    // Delete all Current Document Versions
+    mysqli_query($mysqli, "
+        DELETE FROM `documents`
+        WHERE `document_parent` > 0 AND `document_parent` != `document_id`
+    ");
+
+    mysqli_query($mysqli, "ALTER TABLE `documents` DROP `document_parent`");