added www

lattice-boltzmann.com/content/0-foreword.md

@@ -12,7 +12,7 @@ step of the way. In order to be self consistent it will contain a theoretical pr
 of the lattice Boltzmann method and present the derivation of the numerical method
 as well as a complete implementation. The idea behind this blog is also to
 introduce the reader to novel implementation techniques using functional programming.
-To this aim we will use the hardware agnostic [Futhark](https://futhark-lang.org/)
+To this aim we will use the hardware agnostic [Futhark](https://www.futhark-lang.org/)
 that allows to target a vast amount of architectures (single/multi-core CPU to any
 possible GPU).