CAPTCHA_LENGTH=0 disables captchas

Change-Id: I4c7ec6e2176019a86240bfda3cbabe3644a7afe6
diff --git a/templates/register.htm b/templates/register.htm
index cc15175..87753f8 100644
--- a/templates/register.htm
+++ b/templates/register.htm
@@ -144,6 +144,8 @@
             </div>
         </div>
     </div>
+
+    <?php if($CAPTCHA_LENGTH > 0): ?>
     <!--captcha here-->
     <div class="form-outline mb-3">
         <label class="form-label font-weight-bold" for="form3Example4">Captcha</label>
@@ -161,6 +163,7 @@
                 Type what you see on the image above.
             </div>
     </div>
+    <?php endif; ?>
 
     <!-- Submit button -->
     <button name="type" value="register" type="submit" class="btn btn-primary float-right btn-md">Sign up</button>