Add migration step to the parser setup
Add migration step to the parser setup

Also simplifies calls a wee bit. Relies on eregs/regulations-parser#310 to be
merged (and Docker hub to rebuild that image)

eregs/regulations-site,eregs/regulations-site,eregs/regulations-site,18F/regulations-site,18F/regulations-site,eregs/regulations-site,18F/regulations-site,18F/regulations-site