README.md: add "upgrade" instructions and add port config for public nodes.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

README.md

@@ -19,23 +19,26 @@ JSON-RPC interface is documented in the following manual pages:
 
 Steps:
 
+0.  If you're running a previous version, you'll need to shut it down
+    (maybe close channels first) and delete the $HOME/.lightning directory.
 1.  [Install and compile](INSTALL.md) the requirements.
 2.  Make sure bitcoind is running in testnet mode, and has the latest
     blocks.
 3.  Get some test bitcoins, such as from [TPs' testnet faucet](http://tpfaucet.appspot.com/).
+3.  If you want others to connect to your lightningd, create $HOME/.lightning/config and put `port=8334` in it (or any other port).
 4.  Run `daemon/lightningd`.
-5.  Run `daemon/lightning-cli getinfo` to check it's working.
-6.  Find a node using `daemon/lightning-cli getnodes` (this will populate
+6.  Run `daemon/lightning-cli getinfo` to check it's working.
+7.  Find a node using `daemon/lightning-cli getnodes` (this will populate
     over time).
-7.  Create a new connection to the node using `contrib/lightning-open-channel
+8.  Create a new connection to the node using `contrib/lightning-open-channel
     ADDRESS PORT AMOUNT` where AMOUNT is in BTC (.04294967 is the maximum
     possible).  If successful, this will return only once a block has been
     mined with the funding transaction in it.
-8.  You can create more channels if you wish.
-9.  You can accept payment using `daemon/lightning-cli invoice
+9.  You can create more channels if you wish.
+10.  You can accept payment using `daemon/lightning-cli invoice
     MILLISATOSHI LABEL`; it will give you a payment hash to give to the
     payer.
-10. You can send payments using `contrib/lightning-pay DEST-ID MILLISATOSHI PAYMENT-HASH`.
+11. You can send payments using `contrib/lightning-pay DEST-ID MILLISATOSHI PAYMENT-HASH`.
 
 Final note: This is very much a testbed and work in progress; expect
 All The Things to change, all the time.