✨ Add user register mutation

🔥 Remove a bunch of legacy code

templates/inventory_add.html

@@ -25,7 +25,7 @@
                     {{ form }}
 
                     <input type="submit" value="Legg til" class="btn btn-primary btn-lg" />
-                    <a href="{% url 'inventory' %}" class="btn btn-default" />Tilbake</a>
+                    <a href="{% url 'inventory' %}" class="btn btn-default">Tilbake</a>
                 </form>
             </div>
         </section>