Fix new event creation
Fix new event creation

parent_id should be mass-assignable by admin
ondrocks/openconferenceware,mynameisfashanu/openconferenceware,mynameisfashanu/openconferenceware,mynameisfashanu/openconferenceware,osbridge/openconferenceware,osbridge/openconferenceware,osbridge/openconferenceware,ondrocks/openconferenceware,ondrocks/openconferenceware,mynameisfashanu/openconferenceware,ondrocks/openconferenceware,osbridge/openconferenceware