Added secondary_db_* columns to external_db
Added secondary_db_* columns to external_db

willmclaren/ensembl,danstaines/ensembl,at7/ensembl,Ensembl/ensembl,at7/ensembl,muffato/ensembl,Ensembl/ensembl,Ensembl/ensembl,mjg17/ensembl,muffato/ensembl,james-monkeyshines/ensembl,at7/ensembl,james-monkeyshines/ensembl,danstaines/ensembl,mjg17/ensembl,Ensembl/ensembl,at7/ensembl,mjg17/ensembl,mjg17/ensembl,danstaines/ensembl,muffato/ensembl,willmclaren/ensembl,james-monkeyshines/ensembl,muffato/ensembl,james-monkeyshines/ensembl