Make sure a new symbol is not created each time each time a page load
(see http://brakemanscanner.org/docs/warning_types/denial_of_service/)
Make sure the redirection value cannot be spoofed to another host (http://brakemanscanner.org/docs/warning_types/redirect/)
Make sure the redirection value cannot be spoofed to another host (http://brakemanscanner.org/docs/warning_types/redirect/)
don't display unescaped use generated string (http://brakemanscanner.org/docs/warning_types/cross_site_scripting/)
security :  whitelist what class can be used (http://brakemanscanner.org/docs/warning_types/remote_code_execution/)
Escape link href