add template files and compose file, fix syntax errors in template

Models/Database.php

@@ -0,0 +1,35 @@
+<?php
+class Database {
+    /**
+     * @var Database
+     */
+    protected static $_dbInstance = null;
+    /**
+     * @var PDO
+     */
+    protected $_dbHandle;
+
+    public function getDbConnection(): PDO
+    {
+        return $this->_dbHandle;
+    }
+    public static function getInstance(): ?Database
+    {
+        if(self::$_dbInstance == null) {
+            self::$_dbInstance = new self();
+        }
+        return self::$_dbInstance;
+    }
+
+    private function __construct() {
+        try {
+            $this->_dbHandle = new PDO("sqlite:Databases/ecobuddy.sqlite");
+        }
+        catch (PDOException $e) {
+            echo $e->getMessage();
+        }
+    }
+    public function __destruct() {
+        $this->_dbHandle = null; // destroys the PDO handle when no longer needed
+    }
+}