updated README.md

Author: Jani Giannoudis

README.md

@@ -1,3 +1,14 @@
 <h1>Payroll Engine DbQuery</h1>
 
 SQL Server query application for the Payroll Engine using SQL Server [Management Objects](https://learn.microsoft.com/en-us/sql/relational-databases/server-management-objects-smo/overview-smo?view=sql-server-ver16).
+
+## Commands
+| Command                 | Description                                      |
+|:--|:--|
+| `Query`                 | Execute a query on SQL-Server                    |
+| `TestServer`            | Test if SQL-Server is available                  |
+| `TestHttpConnection`    | Test HTTP conection is available                 |
+| `Parser`                | Parse URL with variable support                  |
+| `TestSqlConnection`     | Test if SQL-Server database is available         |
+| `TestVersion`           | Test SQL-Server database version                 |
+| `TestEmptyTable`        | Test for empty SQL-Server database table         |