Fix peerjs command

There was a typo, path mypapp instead of myapp

README.md

@@ -21,7 +21,7 @@ npm install
 3. Run the server:
 
 ```bash
-$> peerjs --port 9000 --key peerjs --path /mypapp
+$> peerjs --port 9000 --key peerjs --path /myapp
 ```
 
 Or, create a custom server:
@@ -139,4 +139,4 @@ This will start a peerjs server on port 9000 exposed on port 9000.
 Discuss PeerJS on our Google Group:
 https://groups.google.com/forum/?fromgroups#!forum/peerjs
 
-Please post any bugs as a Github issue.
+Please post any bugs as a Github issue.