Ruby 1.9.2+ compatibility: Fix require statement

Fix require statement, because we can't assume that the pwd is in the LOAD_PATH.

I believe this maintains backwards compatibility with Ruby 1.8.7.
Merge pull request #1 from cb372/fix/require-stmt

Ruby 1.9.2+ compatibility: Fix require statement
Implement user migration

Extract users' first names, last names, email addresses and login names
from the XML.

First and last name extraction is best-effort, as JIRA has only a "name"
field.