Started documenting the upgrade process

Author: jbtronics

docs/upgrade/1_to_2.md

@@ -0,0 +1,27 @@
+---
+layout: default
+title: Upgrade from Part-DB 1.x to 2.x
+nav_order: 1
+has_children: false
+---
+
+# Upgrade from Part-DB 1.x to 2.x
+
+Part-DB 2.0 is a major release that changes a lot of things internally, but it is still compatible with Part-DB 1.x.
+Depending on your preferences, you will have to do some changes to your Part-DB installation, this document will guide
+you through the upgrade process.
+
+## New requirements
+*If you are running Part-DB inside a docker container, you can skip this section, as the new requirements are already
+fulfilled by the official Part-DB docker image.*
+
+Part-DB 2.0 requires at least PHP 8.2 (newer versions are recommended). So if your existing Part-DB installation is still
+running PHP 8.1, you will have to upgrade your PHP version first.
+The minimum required version of node.js is now 20.0 or newer, so if you are using 18.0, you will have to upgrade it too.
+
+Most distributions should have the possibility to get backports for PHP 8.4 and modern nodejs, so you should be able to
+easily upgrade your system to the new requirements. Otherwise, you can use the official Part-DB docker image, which
+ships all required dependencies and is always up to date with the latest requirements, so that you do not have to worry
+about the requirements at all.
+
+

docs/upgrade/index.md

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+---
+layout: default
+title: Upgrade
+nav_order: 7
+has_children: true
+---
+
+This section provides information on how to upgrade Part-DB to the latest version.
+This is intended for major release upgrades, where requirements or things changes significantly.

docs/upgrade_legacy.md docs/upgrade/upgrade_legacy.mddocs/upgrade_legacy.md renamed to docs/upgrade/upgrade_legacy.md

@@ -2,6 +2,7 @@
 layout: default
 title: Upgrade from legacy Part-DB version (<1.0)
 nav_order: 100
+redirect_from: /upgrade_legacy
 ---
 
 # Upgrade from legacy Part-DB version