📝 Docs for @tom-smith-okta's Docker install

 - Describe process for Docker-based install

Resolves oktadev#188

Readme.MD

@@ -44,14 +44,30 @@ This tool has been verified to work on macOS Sierra, High Sierra, Windows Server
  ```
 2. Customize **~/.okta/config.properties** to reflect your Okta and Amazon Web Services setup
 
+### Docker
+
+1. Copy `config.properties` to `~/.okta/config.properties` and set
+ **OKTA_ORG** and **OKTA_AWS_APP_URL** appropriately. For example,
+
+ ```properties
+ OKTA_ORG=acmecorp.oktapreview.com
+ OKTA_AWS_APP_URL=https://acmecorp.oktapreview.com/home/amazon_aws/0oa5zrwfs815KJmVF0h7/137
+ ```
+2. Run this command:
+ ```shell
+ docker run -v ~/.okta/config.properties:/root/.okta/config.properties -it tomsmithokta/okta-awscli-java
+ ```
+
+Read more at [@tom-smith-okta's okta-awscli-java Docker repo](https://hub.docker.com/r/tomsmithokta/okta-awscli-java/).
+
 ### Manual install
 
 Create a `.okta` directory in your home directory. For example, `~/.okta`.
 
 Download the latest release JAR and put it in `.okta`:
 https://github.com/oktadeveloper/okta-aws-cli-assume-role/releases
 
-Copy `config.properties` to `.okta/config.properties` and set
+Copy `config.properties` to `~/.okta/config.properties` and set
 **OKTA_ORG** and **OKTA_AWS_APP_URL** appropriately. For example,
 
 ```properties