cbmi/varify — pull request #289 by ryanjohara (2014-05-05 15:41:06+00:00)
Title: Convert cohort_variant and result primary key types to bigint

Backwards migration is NOT supported.
MySQL, Oracle, and SQLite are NOT supported.
ONLY forward migration in PostgreSQL is supported.
Resolves #222

Signed-off-by: Ryan O'Hara