make listening address configurable

README.md

@@ -33,10 +33,19 @@ From there on `cargo run` and `cargo build` and so on can be used.
 
 # Configuration
 
-The binary takes exactly one argument, the path to the calibre library folder.
+```
+Usage: little-hesinde [OPTIONS] -- <LIBRARY_PATH>
 
-The listening port is hardcoded to `3000` for now, as is the listening on all
-interfaces.
+Arguments:
+  <LIBRARY_PATH>  Calibre library path
+
+Options:
+  -l, --listen-address <LISTEN_ADDRESS>  Address to listen on [default: [::1]:3000]
+  -h, --help                             Print help
+  -V, --version                          Print version
+```
+
+Example: `little-hesinde -l [::]4000 -- ~/Documents/library/`
 
 # Usage