Merge pull request #13 from Qu4tro/fix_min_value_0

Fix minimum as zero case.

Author: Lukas Vinclav

admin_numeric_filter/templates/admin/filter_numeric_slider.html

@@ -10,7 +10,7 @@
 
         <h3>{% blocktrans with filter_title=title %}By {{ filter_title }}{% endblocktrans %}</h3>
 
-        {% if choice.min and choice.max and choice.step %}
+        {% if choice.min is not None and choice.max is not None and choice.step %}
             <div class="admin-numeric-filter-slider-tooltips">
                 <span class="admin-numeric-filter-slider-tooltip-from">{{ choice.value_from }}</span>
                 <span class="admin-numeric-filter-slider-tooltip-to">{{ choice.value_to }}</span>
@@ -32,4 +32,4 @@ <h3>{% blocktrans with filter_title=title %}By {{ filter_title }}{% endblocktran
             </div><!-- /.admin-numeric-filter-slider-error -->
         {% endif %}
     </form>
-{% endwith %}
+{% endwith %}