Did you look into using the grails mongo driver here? https://grails.org/plugins/mongodb. This plugin automatically adds the Mongodb java driver and the equivalent helper beans to grab db connections right in your servers. It also primarily adds GORM support. Add the following to your BuildConfig.groovy plugins block:
plugins {
compile ":mongodb:3.0.1"
}
Also, depends on the version of grails you are using. This is recommended for grails 2.3.7 or above. However, if you are using anything2.3.7 or below you need to add this to your BuildConfig.groovy
dependencies {
compile 'org.grails:grails-datastore-gorm:3.0.4.RELEASE'
compile 'org.grails:grails-datastore-core:3.0.4.RELEASE'
test 'org.grails:grails-datastore-simple:3.0.4.RELEASE'
}