NEW: Make teaching_period has many units
NEW: Make teaching_period has many units

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