Add PostgresSQL support (⚠️Development)

postgresql.js

@@ -0,0 +1,15 @@
+/* PostreSQL */
+const pgsync = require('pg-sync');
+
+class PostgreSQL_Database {
+    constructor (host, port, database, clientOptions={}) {
+        this.client = new pgsync.Client(clientOptions);
+        client.connect(`host=${host} port=${port} dbname=${database}`);
+        
+        this.client.begin();
+        this.client.setIsolationLevelSerializable();
+        
+        // this.client.query(queryText, [params]); -> execute command with SELECT *
+        // (this.client.prepare(queryText)).execute([params]); -> execute command without SELECT *
+    }
+}