split and convert competition.scss
save competition times with the appropriate DST offset

my solution to working around whatever local time offset issue had
assumed that ActiveSupport::TimeZone#utc_offset took daylight savings
into account, but it doesn't.
refactor '.leave' button to be more reusable

the button for leaving teams used a style rule that is very helpful else
(changing the border and font color to the error color when hovered
over). This extracts that behavior into a more semantically-general
class called irreversible.
offer option to delete competitions

the "cancel event" button has been added to the competition view. there
really should be a confirmation step to avoid accidently destroying it.
add organizer association to compeititions

there needs to be an organizer level of permissions that allow a
non-admin user to edit/delete individual competitions and perhaps send
out notifications or publish updates in the future.
create new helper to check for competition organizer

in order to actually apply checks for the organizers we should have a
simple helper to use in views.