replace hard-coded values with config variables
replace hard-coded values with config variables

willmclaren/ensembl-rest,helensch/ensembl-rest,ens-lgil/ensembl-rest,ens-lgil/ensembl-rest,willmclaren/ensembl-rest,willmclaren/ensembl-rest,ens-lgil/ensembl-rest,willmclaren/ensembl-rest,willmclaren/ensembl-rest,helensch/ensembl-rest,helensch/ensembl-rest,ens-lgil/ensembl-rest,ens-lgil/ensembl-rest,helensch/ensembl-rest,helensch/ensembl-rest