Web dev's crawler took down major online bookstore by buying too many books

Forgot one setting, for one subdomain, and caused an hour of severe errors
Who, Me? Thank you, dear reader, for tearing yourself away from Black Friday and Cyber Monday sales long enough to visit The Register, just in time for this fresh installment of Who, Me? It's the reader-contributed column in which we share your stories of unforced errors, and how you bounced back afterwards.…