change deploy.sh without mysql, now that we are moving to postgres
prioritise postgres in doc/update/patch_versions.md, assume postgres in doc/update/ruby.md
 Merge branch 'update/deploy.sh' into 'master'

change mysql to postgres in some of the docs and scripts

* update deploy.sh, install gem without mysql, now that we want to use postgres instead
* update update_patch.md to assume postgres before mysql
* update ruby.md, to assume postgres