On Fedora, install Groovy with yum.

Then, download Grails and follow the guide: http://grails.org/doc/latest/guide/gettingStarted.html#requirements

Important: set correct Java and Grails home paths to be used by the engine.

Plain and simple guide for Postgres - https://community.jboss.org/wiki/InstallPostgreSQLOnFedora?_sscc=t

The only difference here was that initdb was called through:

sudo postgresql-setup initdb