[request] Ensure base_url() always has a trailing '/' (closes #3955093) Just as an example, cubicweb.ajax.js is clearly written under the assumption that BASE_URL/baseuri() - which simply contains req.base_url() - has a trailing /.

if repo.system_source.dbdriver == 'postgres':
    sql('ALTER TABLE appears ADD COLUMN weight float')
    sql('UPDATE appears SET weight=1.0 ')