Add nick URL param

Closes: https://todo.sr.ht/~emersion/gamja/40

README.md

@@ -46,7 +46,11 @@ This will start a development HTTP server for gamja. Connect to it and append
 gamja settings can be overridden using URL query parameters:
 
 - `server`: path or URL to the WebSocket server
-- `channels`: comma-separated list of channels to join
+- `nick`: nickname
+- `channels`: comma-separated list of channels to join (`#` needs to be escaped)
+
+Alternatively, the channels can be set with the URL fragment (ie, by just
+appending the channel name to the gamja URL).
 
 ## Configuration file
 

components/app.js

@@ -253,6 +253,9 @@ export default class App extends Component {
 				connectParams.serverURL = queryParams.server;
 			}
 		}
+		if (queryParams.nick) {
+			connectParams.nick = queryParams.nick;
+		}
 		if (queryParams.channels) {
 			connectParams.autojoin = queryParams.channels.split(",");
 		}