message: Sync: Replicate AddColumn(Set)
diff: @@ -353,6 +353,13 @@ void SyncReplication::insert_column(const Table* table, ColKey col_key, DataType
  REALM_ASSERT(key_type == type_String);
  instr.key_type = get_payload_type(key_type);
  }
  + else if (col_key.is_set()) {
  + instr.collection_type = CollectionType::Set;
  + auto value_type = table->get_column_type(col_key);
  + REALM_ASSERT(value_type != type_LinkList);
  + instr.type = get_payload_type(value_type);
  + instr.key_type = Instruction::Payload::Type::Null;
  + }
  else {
  REALM_ASSERT(!col_key.is_collection());
  instr.collection_type = CollectionType::Single;
  