[FIX] website: auto enable multi website when creating a second website

Before this commit, you need to check manually multi website.
And demo data create 2 websites by default, but don't check it.

addons/website/models/website.py

@@ -125,6 +125,12 @@ class Website(models.Model):
 
         res = super(Website, self).create(vals)
         res._bootstrap_homepage()
+
+        if not self.env.user.has_group('website.group_multi_website') and self.search_count([]) > 1:
+            all_user_groups = 'base.group_portal,base.group_user,base.group_public'
+            groups = self.env['res.groups'].concat(*(self.env.ref(it) for it in all_user_groups.split(',')))
+            groups.write({'implied_ids': [(4, self.env.ref('website.group_multi_website').id)]})
+
         return res
 
     @api.multi

addons/website/views/res_config_settings_views.xml

@@ -25,7 +25,7 @@
                                 </div>
                             </div>
                         </div>
-                        <h2>Website</h2>
+                        <h2>Website <button name="action_website_create_new" type="object" string="New" class="ml-2 btn btn-link" icon="fa-plus" groups="!website.group_multi_website"/></h2>
                         <div class="row mt16 o_settings_container" id="website_settings">
                             <div class="col-12  o_setting_box" id="website_action_setting">
                                 <button name="website_go_to" type="object" string="Go to Website" class="btn btn-primary" icon="fa-globe"/>