Add a key for running remote topgrades

README.md

@@ -154,3 +154,8 @@ The configuration should be placed in the following paths depending by the opera
 * **macOS** - `~/Library/Preferences/topgrade.toml`
 * **Windows** - `%APPDATA%/topgrade.toml`
 * **Other Unix systems** - `~/.config/topgrade.toml`
+
+## Remote execution
+You can specify a key called `remote_topgrades` in the configuration file. This key should contain a
+list of hostnames that have topgrade installed on them. Topgrade will execute Topgrades on these
+remote hosts.