message: Add missed step in install instruction
diff: @@ -21,7 +21,9 @@ cd swap.react
  npm i
  ```
  -3) For dev mode `npm run start`, for prod `npm run build`
  +3) Do `git submodule update` in swap.react directory
  +
  +4) For dev mode `npm run start`, for prod `npm run build`
  ```
  npm run start
  