install_and_upgrade.md: link to https://www.stackage.org/stack
install_and_upgrade.md: link to https://www.stackage.org/stack

Heather/stack,deech/stack,vigoo/stack,rvion/stack,lukexi/stack,mathhun/stack,achernyak/stack,mrkkrp/stack,MichielDerhaeg/stack,rubik/stack,harendra-kumar/stack,Blaisorblade/stack,rubik/stack,mrkkrp/stack,supermario/stack,luigy/stack,AndreasPK/stack,juhp/stack,AndrewRademacher/stack,Fuuzetsu/stack,anton-dessiatov/stack,rvion/stack,luigy/stack,MichielDerhaeg/stack,phadej/stack,martin-kolinek/stack,mathhun/stack,phadej/stack,narrative/stack,sjakobi/stack,deech/stack,Blaisorblade/stack,lukexi/stack,Fuuzetsu/stack,supermario/stack,Heather/stack,achernyak/stack,fizruk/stack,harendra-kumar/stack,fizruk/stack,sjakobi/stack,AndrewRademacher/stack,juhp/stack,keent/stack,AndreasPK/stack,vigoo/stack,anton-dessiatov/stack,keent/stack,narrative/stack,martin-kolinek/stack