[Replicant]

The easiest way to include the login form is via iframe. When someone logs in, they will be redirected to the forums.

<iframe id="idLoginIframe" class="js-menu__login-iframe b-menu__login-iframe" src="http://www.example.com/forums/auth/login-form"></iframe>

This will display the login form on your page. You can set the CSS to display none, add a div with a login button to create the nav bar and use jquery or javascript to toggle the form when someone clicks the button. Use absolute positioning and z-index to have the form overlap the page like a dropdown. This is the easiest way to include the vb login form to an outside page.