hide hash field if empty on objective.html

app/templates/objective.html

@@ -27,10 +27,12 @@
                     {{ wtf.form_field(form.objective_name, value=objective.name, class='form-control') }}
                     {{ wtf.form_field(form.latitude, class='form-control', type='number', value=objective.latitude, min='-90', max='90', step='0.00001') }}
                     {{ wtf.form_field(form.longitude, class='form-control', type='number', value=objective.longitude, min='-180', max='181', step='0.00001') }}
+                    {% if objective.hash %}
                     <div class="form-group">
                         <label for="hash">Hash</label>
                         <p>{{ objective.hash }}</p>
                     </div>
+                    {% endif %}
                     {{ wtf.form_field(form.submit, class='btn btn-primary') }}
                 </form>
                 {% if objective.hash %}