Oasis fans have faced concert chaos this morning after websites’ selling tickets crashed when tens of thousands of people tried to nab tickets from the general sale. Tickets went on sale at 9am after the legendary Britpop group announced their long-awaited reunion on Tuesday. Brothers Noel and Liam Gallagher appear to have put aside their differences as they look set to appear onstage for the first time since the band’s split in 2009. Tickets went on sale in the UK at 9am on Ticketmaster, Gigs and Tours and See Tickets. Tickets to concerts held at Dublin’s Croke Park went on sale on Ticketmast…