My webpage is redirecting me to /defaultsite instead of index.php

After moving the rootDirectory of apache2 from

/var/www/html

to

/var/www/html/MyFolder

because I didn't want my website to be "http://ift.tt/2i4bB1H" but now I have to type in "http://ift.tt/2iBjCZ3" (that works)

What do I have to change so I can just type in "www.website.de" and the index.php is displayed automatically

I didn't change much. Only the rootDirectory 000-default.conf.