improve the wording

backend/templates/settings.html

@@ -7,7 +7,7 @@
     <form class="pure-form pure-form-stacked" action="/settings" method="POST">
         <fieldset>
             <div class="pure-control-group">
-                <label for="minutes">Minutes between recheck</label>
+                <label for="minutes">Maximum time in minutes until recheck.</label>
                 <input type="text" id="minutes" required="" name="minutes" value="{{minutes}}"
                        size="5"/>
                 <span class="pure-form-message-inline">This is a required field.</span>