Require open-uri

[ryanb]

From a GitHub message:

I fixed a slight problem with the DB reload which was due to a missing "require 'open-uri'" in the "lib/xapit-sync.rb" file.

View repository: http://github.com/k33l0r/xapit-sync/tree/master

[BDQ]

Yeah I've seen this issue too, +1 for this fix