title: Rails Active Record query -- 'or' conditions
body: <p>I have a jobs table; each job has a start_date and an end_date. For a given month I want to pull all jobs that were "running" in any part of, or all of some month. The problem is how to write the query for the 5 different "or" conditions needed to capture the notion of a job running in all of or any part of the month. So, I need all jobs that started before the beginning of the month and ended during the month <strong>OR</strong> all jobs that started and ended during the month <strong>OR</strong> all jobs that started in the month and finished after the end  of the month... Well, there is three of the five. So in the Jobs.where clause, how is the "or" compactly expressed?</p>