message: update express docker production docs
diff: @@ -46,6 +46,35 @@ Environment: test
  Base URI: http://0.0.0.0:4000
  ```
  +### Docker in production
  +
  +When running BitGo Express in production, we strongly recommended using HTTPS to secure your connections.
  +
  +If you have your own certificate, you can use it.
  +
  +Or, to generate a self-signed certificate, first make a directory and navigate into it:
  +```bash
  +$ mkdir certs
  +$ cd certs
  +```
  +Then do the following and fill out the information that it prompts you for:
  +```bash
  +$ openssl req -newkey rsa:2048 -nodes -keyout cert.key -x509 -days 3650 -out cert.crt
  +```
  +This will output a key file ```cert.key``` and certificate file ```cert.crt```
  +
  +Finally you can run your docker container like this (note, replace ```/path/to``` with the full path to your ```certs``` folder):
  +```bash
  +$ docker run -it --volume /path/to/certs:/private -p 4000:4000 bitgosdk/express:latest -p 4000 -k /private/cert.key -c /private/cert.crt -e prod
  +```
  +
  +BitGo Express should start on the specified port, 4000:
  +```
  +BitGo-Express running
  +Environment: prod
  +Base URI: https://0.0.0.0:4000
  +```
  +
  ### Building the docker container
  If you'd like to build the BitGo Express docker container yourself from the source code, first check out the latest release branch **rel/latest**, then run `docker build` from the project root. Here's the commands:
  