the postgresql dialect name for SQLAlchemy is 'postgresql'
require the database::mysql recipe which installs the 'mysql' gem

we need this in the next step and this is the best place to put the
include_recipe (since we can't put it in the provider)
remove confusing comments pointing to outdated URLs
Merge pull request #7 from mapleoin/sqla-dialect

the postgresql dialect name for SQLAlchemy is 'postgresql'
Merge pull request #8 from mapleoin/mysql-gem

install the mysql gem when we use the mysql provider