Open up API and add instructions for get wallet balance

Signed-off-by: Yilun <zyl.skysniper@gmail.com>

README.md

@@ -195,13 +195,27 @@ $ ./nknd
 If you are using Docker then you should run the following command instead:
 
 ```shell
-$ docker run -p 30000-30003:30000-30003 -v $PWD:/nkn -it nkn nknd
+$ docker run -p 30000-30003:30000-30003 -v $PWD:/nkn --name nkn -it nkn nknd
+```
+
+If everything goes well, you should be part of our TestNet now! You can query
+your wallet balance (which includes the Testnet token you've mined) by:
+
+```shell
+$ ./nknc wallet -l balance
+```
+
+or if you are using Docker:
+
+```shell
+$ docker exec -it nkn nknc wallet -l balance
 ```
 
-If everything goes well, you should be part of our TestNet now!
+**Note that Testnet token is for testing purpose only, and may be cleared at any
+time when Testnet resets.**
 
-If not, you may want to check if some of the previous steps went wrong. If the
-problem still persists, [create an
+If anything goes wrong, you may want to check if any of the previous steps went
+wrong. If the problem still persists, [create an
 issue](https://github.com/nknorg/nkn/issues/new) or ask us in our [Discord
 group](#community).
 

api/common/interfaces.go

@@ -1031,8 +1031,8 @@ var InitialAPIHandlers = map[string]APIHandler{
 	"getnodestate":         {Handler: getNodeState, AccessCtrl: BIT_JSONRPC},
 	"getchordringinfo":     {Handler: getChordRingInfo, AccessCtrl: BIT_JSONRPC},
 	"getunspendoutput":     {Handler: getUnspendOutput, AccessCtrl: BIT_JSONRPC},
+	"getbalance":           {Handler: getBalance, AccessCtrl: BIT_JSONRPC},
 	"setdebuginfo":         {Handler: setDebugInfo},
-	"getbalance":           {Handler: getBalance},
 	"registasset":          {Handler: registAsset},
 	"issueasset":           {Handler: issueAsset},
 	"sendtoaddress":        {Handler: sendToAddress},