Update installation.md

doc/installation.md

@@ -4,7 +4,7 @@
 1. *We work on stable, supported and up-to-date versions of packages. We recommend you to do the same.*
 
 ```bash
-$ composer require bitbag/cms-plugin
+$ composer require bitbag/cms-plugin --no-scripts
 ```
 
 2. Add plugin dependencies to your `config/bundles.php` file:
@@ -88,12 +88,15 @@ you will probably need to change the extension of the imported file in
 5. Finish the installation by updating the database schema and installing assets:
 
 ```
+$ bin/console cache:clear
 $ bin/console doctrine:migrations:diff
 $ bin/console doctrine:migrations:migrate
 $ bin/console assets:install --symlink
 $ bin/console sylius:theme:assets:install --symlink
 ```
 
+Note. In some cases the `--symlink` option [may trow some errors](https://github.com/Sylius/SyliusThemeBundle/issues/91). If you consider running the commands without `--symlink` option, please keep in mind to run them on every potential plugin update.
+
 6. Add plugin assets to your project
 
 We recommend you to use Webpack (Encore), for which we have prepared four different instructions on how to add this plugin's assets to your project: