We never published this since ESRI caught up to us with related table editing in Collector, but prior to the related table editing functionality in Collector we created a workaround using ModelBuilder for monthly volunteer stream monitoring data entry. The monitoring data is stored in a versioned enterprise related table associated with the stream segment feature class, so we created a scheduled model running on our ArcGIS Server to copy the stream segments to a new feature class (to account for stream reaches that may have been added), strip the attributes from the feature class, then create and append an unpopulated copy of the related table as the new feature class attribute schema. Then the new 'edit feature class' would be published as a feature service from ArcGIS for Server to AGOL. Volunteers would then make their (once monthly or quarterly) edits to the feature class attribute table. Then a second model would be run (scheduled monthly for us) to copy the edited feature records, checking a required field to omit any empty records, and then those records are appended to the versioned enterprise related table. It looks like we may need to revisit this workaround until related table editing is enabled in AGOL desktop.