add SQL DDL script for the sqlite database

db_ddl.sql

@@ -0,0 +1,26 @@
+CREATE TABLE Documents (
+	ID INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
+	Title TEXT NOT NULL,
+	Description TEXT,
+	Author TEXT,
+	Published TEXT,
+	URL TEXT NOT NULL
+);
+
+CREATE TABLE DocumentsToTags (
+	Document INTEGER NOT NULL,
+	Tag INTEGER NOT NULL
+);
+
+CREATE TABLE Tags (
+	ID INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
+	Name TEXT NOT NULL,
+	Description TEXT,
+	Parent INTEGER
+);
+
+CREATE TABLE Users (
+	ID INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
+	Username TEXT NOT NULL,
+	Password TEXT NOT NULL
+);