Update index.html.md (#2191)
Update index.html.md (#2191)

add DSN as link to go-sql-driver/mysql to know the syntax
hartsock/vault,mgk/vault,mgk/vault,Aloomaio/vault,ryon/vault,mymercurialsky/vault,LolalyLuo/vault,jgcallero/vault,deverton/hashicorp-vault,jmhardison/vault,wjam/vault,naunga/vault,Banno/vault,jmhardison/vault,deverton/hashicorp-vault,lirao/vault,rnaveiras/vault,joelthompson/vault,MonsantoCo/vault,hashicorp/vault,hartsock/vault,hashicorp/vault,joelthompson/vault,jgcallero/vault,kingland/vault,tallpauley/vault,jmhardison/vault,hartsock/vault,rnaveiras/vault,rnaveiras/vault,hartsock/vault,LolalyLuo/vault,rnaveiras/vault,jam-pot/vault,Aloomaio/vault,quixoten/vault,lemondrank/vault,joelthompson/vault,Aloomaio/vault,chrishoffman/vault,kingland/vault,kingland/vault,hashicorp/vault,Caiyeon/vault,Caiyeon/vault,Aloomaio/vault,lirao/vault,mgk/vault,hashicorp/vault,lemondrank/vault,wjam/vault,hartsock/vault,quixoten/vault,jmhardison/vault,hashicorp/vault,jmhardison/vault,jam-pot/vault,michaelansel/vault,tallpauley/vault,mymercurialsky/vault,MonsantoCo/vault,quixoten/vault,joelthompson/vault,hashicorp/vault,michaelansel/vault,kingland/vault,mgk/vault,kingland/vault,chrishoffman/vault,ryon/vault,rnaveiras/vault,naunga/vault,Banno/vault,quixoten/vault