docs: add doc for config

docs/ulwgl.5.scd

@@ -0,0 +1,56 @@
+ulwgl(5)
+
+# NAME
+
+ulwgl-run - configuration file
+
+# DESCRIPTION
+
+ulwgl-run can optionally read a configuration file instead of reading
+environment variables set from the command line. The configuration file for
+ulwgl-run must be written in valid Tom's Obvious Minimal Language (TOML).
+
+In the configuration file, the table *ulwgl* is required as well as the keys
+*prefix*, *proton* and *exe* which all must be basic strings. e.g.:
+
+```
+[ulwgl]
+prefix = "~/WINE/epic-games-store"
+exe = "~/EpicGamesLauncher.exe"
+proton = "~/.local/share/Steam/compatibilitytools.d/GE-Proton30"
+```
+
+Afterwards, run the command:
+```
+$ ulwgl-run --config config.toml
+```
+
+# [ulwgl] SECTION
+
+*exe*
+	Path to the game executable to run. Value must be a basic *string*.
+
+*proton*
+	Path to a Proton directory. Value must be a basic *string*.
+
+*prefix*
+	Path to a WINE prefix directory. Value must be a basic *string*.
+
+*game_id*
+	The ULWGL id to assign to the game. Depending on the value assigned, a Proton
+	fix will be applied to the prefix if available. Please refer to the ULWGL
+	database for an extended list of game ids.
+
+*store*
+	The distribution platform of the executable. Value must be a basic *string*.
+	Expects the values: egs, gog, battlenet, amazon, humble, itchio, and ubisoft.
+
+*launch_args*
+	Launch arguments for the executable. Value must be a basic *string*.
+	Assumes each argument is space-separated.
+
+# AUTHORS
+
+Maintained by Open Wine Components members, and assisted by other open source
+contributors. For more information about ULWGL development, see
+https://github.com/Open-Wine-Components/ULWGL-launcher.