If you need to do redirect from urls without tail slash to urls with slash, you can simply add this lines in your .htaccess:
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-l
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !(.*)/$
RewriteRule ^(.*[^/])$ http://www.site.ru/$1/ [L,R=301]