# paging_action - the action that will be linked back to from view
def list (target_user = nil, paging_action = 'list')
@title = 'public GPS traces'
+ @title += " tagged with #{params[:tag]}" if params[:tag]
@traces_per_page = 20
page_index = params[:page] ? params[:page].to_i - 1 : 0 # nice 1-based page -> 0-based page index