added slight denormalisation: variation_group_feature.variation_group_name column
added slight denormalisation: variation_group_feature.variation_group_name column

dbolser/ensembl-variation,willmclaren/ensembl-variation,Ensembl/ensembl-variation,Ensembl/ensembl-variation,willmclaren/ensembl-variation,willmclaren/ensembl-variation,Ensembl/ensembl-variation,dbolser/ensembl-variation,Ensembl/ensembl-variation,dbolser/ensembl-variation,dbolser-ebi/ensembl-variation,dbolser/ensembl-variation,dbolser-ebi/ensembl-variation,willmclaren/ensembl-variation,willmclaren/ensembl-variation,Ensembl/ensembl-variation,dbolser-ebi/ensembl-variation