Added migration guide

Author: jbtronics

docs/upgrade/1_to_2.md

@@ -25,8 +25,64 @@ ships all required dependencies and is always up to date with the latest require
 about the requirements at all.
 
 ## Changes
+* Configuration is now preferably done via a web settings interface. You can still use environment variables, these overwrite
+the settings in the web interface. Existing configuration will still work, but you should consider migriting them to the
+web interface as described below.
 * The `config/banner.md` file that could been used to customize the banner text, was removed. You can now set the banner text
   directly in the admin interface, or by setting the `BANNER` environment variable. If you want to keep your existing
   banner text, you will have to copy it from the `config/banner.md` file to the admin interface or set the `BANNER`
   environment variable.
- 
+* The parameters `partdb.sidebar.items`, `partdb.sidebar.root_node_enable` and `partdb.sidebar.root_expanded` in `config/parameters.yaml`,
+were removed. You can configure them now directly in the admin interface.
+* Updated icon set. As fontawesome 7 is now used, some icons have changed slightly.
+
+## Upgrade installation
+
+The upgrade process works very similar to a normal (minor release) upgrade.
+
+### Direct installation
+
+**Be sure to execute the following steps as the user that owns the Part-DB files (e.g. `www-data`, or your webserver user). So prepend a `sudo -u wwww-data` where necessary.**
+
+1. Make a backup of your existing Part-DB installation, including the database, data directories and the configuration files and `.env.local` file.
+The `php bin/console partdb:backup` command can help you with this.
+2. Pull the v2 version. For git installation you can do this with `git checkout v2.0.0` (or newer version)
+3. Run `composer install --no-dev -o` to update the dependencies.
+4. Run `yarn install` and `yarn build` to update the frontend assets.
+5. Rund `php bin/console doctrine:migrations:migrate` to update the database schema.
+6. Clear the cache with `php bin/console cache:clear`.
+7. Open your Part-DB instance in the browser and log in as an admin user.
+8. Go to the user or group permissions page, and give yourself (and other administrators) the right to change system settings (under "System" and "Configuration").
+9. You can now go to the settings page (under "System" and "Settings") and check if all settings are correct.
+10. Parameters which were previously set via environment variables are greyed out and cannot be changed in the web interface. 
+If you want to change them, you must migrate them to the settings interface as described below.
+
+### Docker installation
+1. Make a backup of your existing Part-DB installation, including the database, data directories and the configuration files and the file where you configure the docker environment variables.
+2. Stop the existing Part-DB container with `docker compose down`
+3. Ensure that your docker compose file uses the new latest images (either `latest` or `2` tag).
+4. Pull the new images with `docker compose pull` and start the container with `docker compose up -d`
+5. If you have database automigration disabled, run `docker exec --user=www-data partdb php bin/console doctrine:migrations:migrate` to update the database schema.
+6. Open your Part-DB instance in the browser and log in as an admin user.
+7. Go to the user or group permissions page, and give yourself (and other administrators)
+the right to change system settings (under "System" and "Configuration").
+8. You can now go to the settings page (under "System" and "Settings")
+9. Parameters which were previously set via environment variables are greyed out and cannot be changed in the web interface. 
+If you want to change them, you must migrate them to the settings interface as described below.
+
+## Migrate environment variable configuration to settings interface
+As described above, configuration can now be done via the web interface, and can be overwritten by environment variables, so
+that existing configuration should still work. However, if a parameter is set via an environment variable, it cannot be changed in the web interface.
+To change it, you must migrate your environment variable configuration to the new system.
+
+For this there is the new console command `settings:migrate-env-to-settings`, which reads in all environment variables used to overwrite
+settings and write them to the database, so that you can safely delete them from your environment variable configuration afterwards, without
+loosing your configuration.
+
+To run the command, execute `php bin/console settings:migrate-env-to-settings --all` as webserver user (or run `docker exec --user=www-data -it partdb php bin/console settings:migrate-env-to-settings --all` for docker containers).
+It will list you all environment variables, it found and ask you for confirmation to migrate them. Answer with `yes` to migrate them and hit enter.
+
+After the migration run successfully, the contents of your environment variables are now stored in the database and you can safely remove them from your environment variable configuration.
+Go through the environment variables listed by the command and remove them from your environment variable configuration (e.g. `.env.local` file or docker compose file), or just comment them out for now.
+
+If you want to keep some environment variables, just leave them as they are, they will still work as before, the migration command only affects the settings stored in the database.