introduce migration guide

Migrating-to-OpenWebRX-1.0.md

@@ -0,0 +1,54 @@
+# Configuration system
+
+The configuration system in OpenWebRX has been completely overhauled in OpenWebRX 1.0. It doesn't offer many new
+settings, the main change is that most configuration can now be performed from the new web configuration interface,
+meaning that editing configuration files should be a thing of the past for normal usage now.
+
+The new configuration system also has a new storage implementation that will replace the familiar `config_webrx.py`
+file. To facilitate the transition, OpenWebRX will still search for and read existing configuration files in the
+established locations, alongside the new storage system, and will combine the two at runtime, with the new configuration
+system taking precedence.
+
+It will not update the old configuration files, but instead write all changes to the new storage system. In
+combination, that means that as soon as you start editing the configuration using the new web configuration, your
+existing settings, along with the modifications, will be written to the new storage system, and your previous
+configuration files will become obsolete. This should ensure a seamless, transparent migration of existing configurations.
+
+Future versions of OpenWebRX will eventually drop the support for the old config files. At this point, the transition
+to the new config system will be complete.
+
+## Hot-wired settings
+
+Most of the settings in the new web configuration have been reconnected in a way that makes them take effect
+immediately. This is especially useful when adjusting device or profile parameters, since this allows you to open
+receiver and config alongside each other and immediately see the effect of your adjustments.
+
+## Introduction of `openwebrx.conf`
+
+Some very fundamental settings (4 in total), that would be hard to change at runtime, have been moved to a new
+configuration file `openwebrx.conf`. This file will be located in `/etc/openwebrx` in most installations, but given the
+nature of these settings, they should not need to be modified very frequently, if at all.
+
+This new configuration also supports a configuration directory structure in `/etc/openwebrx/openwebrx.conf.d`, where you
+can place configuration overrides. This allows customization of these parameters without overriding the packaged
+configuration file.
+
+## Individual files and their migration
+
+`config_webrx.py` is effectively migrated in slices, since its settings are spread across the multiple sections of the
+web configuration. Every section will migrate those settings that are in it, so by the time all sections have been
+edited once, the full file should be migrated.
+
+`bookmarks.json` will be migrated as soon as you start editing bookmarks with the new bookmark editor.
+
+`bands.json` will not be migrated at this point.
+
+# Red Pitaya support
+
+The existing "red_pitaya" device type has been dropped in favor of the new HPSDR support, which also covers the Red
+Pitaya devices.
+
+# `rtltcp_compat` changes
+
+The former settings for the `rtltcp_compat` feature may not be migrated automatically. If this happens, add the new
+"Port for rtl_tcp compatible data" setting to the device and set it to the port number accordingly.