adding trailing slashes to post forms

rowers/templates/paidplans.html

@@ -12,6 +12,11 @@
       hosting costs, we have created paid plans offering extended
       functionality.
     </p>
+    <p>
+      All plans are valid for a year. Recurring payment plans will automatically
+      bill you at the start of a new 12 month period. You can stop your plan
+      at any time in your <a href="/rowers/me/edit/">settings</a>.
+    </p>
 
     <p>
       <table class="plantable shortpadded" width="80%">