Copy the plugins to the directory $RAILS_ROOT/vendor/plugins or check them out from github. For example, if you want to install a redmine charts plugins, check out the code from github and place it in the $RAILS_ROOT/vendor/plugins:
bash# cd $RAILS_ROOT
bash# sudo git clone git://github.com/mszczytowski/redmine_charts.git vendor/plugins/redmine_charts
If the plugin requires a migration, run the following command to upgrade your database (make a db backup first as a precaution):
bash# cd $RAILS_ROOT
bash# sudo rake db:migrate_plugins RAILS_ENV="production" --trace
Restart Redmine
bash# sudo /etc/init.d/apache2 reload
For the plugins list, please follow this link: http://www.redmine.org/wiki/redmine/Plugin_List