Handle both homebrew's mysql and mariadb
Fix bug in Chunker if only 1 record

In a table with a single record, both the `next_to_start` and the
`limit` variables are the same thus never triggering the copy.
Add specs to ensure integrity for 1 record case
Merge pull request #1 from teambox/fix/bug-migrating-single-record

Fix/bug migrating single record