Add options for DB_NAME

[titanismo]

Will be very helpful to have option to choose DB Name.

[grange74]

Hi @titanismo, thanks for the PR.
You will need to modify https://github.com/retrievercommunications/docker-jasperserver/blob/master/entrypoint.sh as well. If you look at lines 18-22, you can do something similar. The line you want to replace is "# js.dbName=jasperserver" with the environment variable.
Below is an extract of the template master.properties file from a recent version.

# database type
dbType=mysql

# database location and connection settings

dbHost=localhost
dbUsername=root
dbPassword=password


# additional database parameters
# (uncomment these if you want non-default settings)

# dbPort=3306

# JasperServer db name, sample db names
# js.dbName=jasperserver
# sugarcrm.dbName=sugarcrm
# foodmart.dbName=foodmart

# web app name
# (set one of these to deploy to a non-default war file name)
# webAppNameCE = jasperserver
# webAppNamePro = jasperserver-pro