code: public static void addSeqRes(Chain modelChain, String sequence) {
  		List<Group> seqResGroups = modelChain.getSeqResGroups();
  		GroupType chainType = getChainType(modelChain.getAtomGroups());
  		for(int i=0; i<sequence.length(); i++){
  			char singleLetterCode = sequence.charAt(i);
  			Group group = null;
  			if(seqResGroups.size()<=i){
  			}
  			else{
  				group=seqResGroups.get(i);
  			}
  			if(group!=null){
  				continue;
  			}
  			group = getSeqResGroup(modelChain, singleLetterCode, chainType);
  			addGroupAtId(seqResGroups, group, i);
  			seqResGroups.set(i, group);
  		}
  	}
docs: Add the missing groups to the SeqResGroups.
  @param modelChain the chain to add the information for
  @param sequence the sequence of the construct