removed symbolic link use

doc/upgrade.rst

@@ -54,17 +54,19 @@ New-admin interface
 ===================
 
 .. note::
-   You don't need to perform these actions if you installed modoboa after 2.0.5.
+   You don't need to perform these actions if you use the installer to upgrade your instance.
 
-New admin interface won't update by itself. To fix this, run the following commands (you need to perform this only one time):
+New admin interface won't update by itself. Run the following commands to update it:
 
 .. sourcecode:: bash
 
    > sudo -u <modoboa_user> -i bash
    > cd <modoboa_instance_dir>
+   > cp frontend/config.json ./
    > rm -rf frontend
-   > ln -s <virtuenv_path>/lib/pythonX.X/site-packages/modoboa/frontend_dist/ frontend/
-
+   > cp -R <virtuenv_path>/lib/pythonX.X/site-packages/modoboa/frontend_dist/ frontend/
+   > cp ./config.json frontend/config.json
+ 
 Extensions
 **********
 

modoboa/core/commands/deploy.py

@@ -273,7 +273,7 @@ class DeployCommand(Command):
         if not os.path.exists(base_frontend_dir):
             return
         frontend_target_dir = "{}/frontend".format(parsed_args.name)
-        os.symlink(base_frontend_dir, frontend_target_dir, True)
+        shutil.copytree(base_frontend_dir, frontend_target_dir)
 
         with open("{}/config.json".format(frontend_target_dir), "w") as fp:
             fp.write("""{