message: add readme on how to add meta for an address
diff: @@ -77,3 +77,24 @@ And then visit http://localhost:4004/?locale=zh-CN
  ## Contribute to Localization?
  Join here to contribute: https://lokalise.co/public/903185115c91ceff0cb2a0.70666943/
  +
  +## How to add meta for an address?
  +
  +- Fork this repo to your own.
  +- Modify `src/api-gateway/address-meta.json` by append you entry to the json list.
  + - Your entry should be follow struct as below
  + ```
  + {
  + "address": "<your address>",
  + "name": "<your address's name>"
  + }
  + ```
  + Ex:
  + ```
  + {
  + "address": "io1et7zkzc76m9twa4gn5xht3urt9mwj05qvdtj66",
  + "name": "iotxplorerio"
  + }
  + ```
  +- Commit & push your changes to your git repo.
  +- Send a PR with title prefix `[ADDRESS-META]` and description of your address if you want to merge into our repo.
  