[doc] Update cubicweb-ctl page about how to run an instance
* remove mention of start/stop/restart/status commands that do not exist anymore
* briefly mention the "pyramid" and point to respective documentation page
* mention that a WSGI server should be used in production
if repo.system_source.dbdriver == 'postgres':
sql('ALTER TABLE appears ADD COLUMN weight float')
sql('UPDATE appears SET weight=1.0 ')