Currently courses are available to all or none.   In order to allow 
institutions to beta test courses in development, model needs to be
enhanced so that courses can made available to individual institutions.

GLS members should have an interface to set availabillity (at the
least as a simple on off, possibly with date ranges as well) for
individual courses for indivdual institutions.

As a rough sketch, first page/selector should allow GLS member to 
choose course (or group of courses) from all available courses, 
second page/selector should
allow selection of group from all available institutions, and third
page/selector should allow "enable" or "disable" (or time range...)