Extract the run command into a script.

[RobertZenz]

The run command mentioned in the README should be extracted into a script so that someone can simply clone the repository and run the script, instead of copying a command.

It can also be shortened, depending on how portable one does want it. For example this is the shortest incarnation I can come up with:

ls -v *.sql | xargs psql -f

However, the -v flag of ls is not portable and is most likely only available in the GNU version...but so is the -V flag of sort, as far as I am aware. So the most portable script is most likely this one:

ls *.sql | sort -n | xargs psql -f

[kmoppel]

A good idea! Could make it more easier for beginners. So I've added a rollout.sh script + changed the SQL scripts so that they could be executed also one by one (added \c + set role)