Best practices:

- Use a boolean variable for each plugin to decide if it has to be installed or removed.

- Provide a task to remove a plugin



To delete a plugin:

1. Downgrade the database 

   cd /srv/redmine/d4science; bundle exec rake redmine:plugins:migrate NAME=plugin_name VERSION=0 RAILS_ENV=production

2. Remove the plugin from the plugins folder (/srv/redmine/d4science/plugins/plugin_name)

3. Restart unicorn (or web server)