Prevent Development modules from being added to configuration management
From Dave Reid on Twitter

Ignoring Development Modules

If you have a certain list of modules that should only be enabled on the development or staging server, then this may be done with the built-in --skip-modules option in the config-export and config-import commands.

For example, if you want to enable the 'devel' module on development systems, but not on production server, you could define the following configuration settings in your drushrc.php file:

# $command_specific['config-export']['skip-modules'] = array('devel');
# $command_specific['config-import']['skip-modules'] = array('devel');


You may then use drush pm-enable to enable the devel module on the development machine, and subsequent imports of the configuration data will not cause it to be disabled again. Similarly, if you make changes to configuration on the development environment and export them, then the devel module will not be listed in the exports.

http://www.drush.org/en/master/config-exporting/#ignoring-development-modules