fixed bug with recaptcha

templates/home.html

@@ -30,7 +30,7 @@
                   {% endif %}
                   <input id="short" name="short" type="text" placeholder="short name" value="{{short_url_prefilled}}"/>
 
-                  {% if recaptchaPrivateKey %}
+                  {% if recaptchaPublicKey %}
                   <button class="g-recaptcha" data-sitekey="{{recaptchaPublicKey}}" data-callback='onSubmit'>short</button>
                   {% else %}
                   <button>short</button>