FIX: Add units to teaching period serializer
FIX: Add units to teaching period serializer

jakerenzella/doubtfire-api,jakerenzella/doubtfire-api,doubtfire-lms/doubtfire-api,doubtfire-lms/doubtfire-api,doubtfire-lms/doubtfire-api,doubtfire-lms/doubtfire-api,jakerenzella/doubtfire-api,jakerenzella/doubtfire-api,jakerenzella/doubtfire-api,jakerenzella/doubtfire-api,doubtfire-lms/doubtfire-api,doubtfire-lms/doubtfire-api,doubtfire-lms/doubtfire-api,jakerenzella/doubtfire-api