add ´unique´ constraint in db init script for username

src/init/init_db.ts

@@ -5,7 +5,7 @@ const db = new Database('./src/lib/data/tatort.db');
 
 let createSQLStmt = `CREATE TABLE IF NOT EXISTS users
         (id INTEGER PRIMARY KEY AUTOINCREMENT,
-            name TEXT NOT NULL,
+            name TEXT NOT NULL UNIQUE,
             pw TEXT NOT NULL)`;
 db.exec(createSQLStmt);