Using Microsoft SQL Server as a database backend
Create a database on your backend, plus a user (and assign it the db_owner role)
In %RDECK_BASE%\server\config\rundeck-config.properties, set the following:
rundeck.projectsStorageType=db
dataSource.dbCreate = update
dataSource.driverClassName = com.microsoft.sqlserver.jdbc.SQLServerDriver
dataSource.url = jdbc:sqlserver://myserver;DatabaseName=RUNDECK
dataSource.username = myusername
dataSource.password = mypassword