Doc: update the install doc with alembic
Doc: update the install doc with alembic

lrocheWB/navitia,pbougue/navitia,francois-vincent/navitia,kinnou02/navitia,fueghan/navitia,xlqian/navitia,fueghan/navitia,patochectp/navitia,patochectp/navitia,stifoon/navitia,antoine-de/navitia,Tisseo/navitia,thiphariel/navitia,lrocheWB/navitia,prhod/navitia,thiphariel/navitia,stifoon/navitia,datanel/navitia,xlqian/navitia,stifoon/navitia,is06/navitia,kinnou02/navitia,ballouche/navitia,is06/navitia,VincentCATILLON/navitia,is06/navitia,VincentCATILLON/navitia,francois-vincent/navitia,prhod/navitia,pbougue/navitia,prhod/navitia,VincentCATILLON/navitia,ballouche/navitia,prhod/navitia,TeXitoi/navitia,Tisseo/navitia,datanel/navitia,kinnou02/navitia,djludo/navitia,djludo/navitia,TeXitoi/navitia,kadhikari/navitia,TeXitoi/navitia,djludo/navitia,CanalTP/navitia,kadhikari/navitia,kadhikari/navitia,CanalTP/navitia,lrocheWB/navitia,kadhikari/navitia,antoine-de/navitia,Tisseo/navitia,patochectp/navitia,Tisseo/navitia,Tisseo/navitia,fueghan/navitia,xlqian/navitia,lrocheWB/navitia,datanel/navitia,pbougue/navitia,ballouche/navitia,thiphariel/navitia,thiphariel/navitia,frodrigo/navitia,frodrigo/navitia,VincentCATILLON/navitia,francois-vincent/navitia,stifoon/navitia,kinnou02/navitia,frodrigo/navitia,CanalTP/navitia,CanalTP/navitia,antoine-de/navitia,ballouche/navitia,TeXitoi/navitia,frodrigo/navitia,fueghan/navitia,xlqian/navitia,xlqian/navitia,patochectp/navitia,is06/navitia,djludo/navitia,datanel/navitia,CanalTP/navitia,antoine-de/navitia,francois-vincent/navitia,pbougue/navitia