Merge pull request oktadev#226 from AlainODea/ao-DOC-clarify-PATH-reqs

📝 Clarify PATH requirements

Readme.MD

@@ -40,6 +40,7 @@ This tool has been verified to work on macOS Sierra, High Sierra, Windows Server
 
 1. Run the following in a Terminal:
  ```bash
+ export PREFIX=/usr/local/bin
  curl 'https://raw.githubusercontent.com/oktadeveloper/okta-aws-cli-assume-role/master/bin/install.sh' | bash
  ```
 2. Customize **~/.okta/config.properties** and set **OKTA_ORG** and **OKTA_AWS_APP_URL** appropriately. For example,
@@ -48,6 +49,7 @@ This tool has been verified to work on macOS Sierra, High Sierra, Windows Server
  OKTA_ORG=acmecorp.oktapreview.com
  OKTA_AWS_APP_URL=https://acmecorp.oktapreview.com/home/amazon_aws/0oa5zrwfs815KJmVF0h7/137
  ```
+3. Make sure **/usr/local/bin** (or whatever $PREFIX/bin is) is in your PATH
 
 ### Docker
 
@@ -97,6 +99,8 @@ Run the program again to see session resumption (you won't be asked for Okta cre
 okta-aws test sts get-caller-identity
 ```
 
+NOTE: **okta-aws** is a function loaded from your shell profile, not a typical program or command stored in a file.
+
 ## Compiling the application
 
 The application was built and compiled with [JetBrains' IntelliJ IDEA](https://www.jetbrains.com/idea/). Note that you don't have to compile the application in order to be able to execute it, since the compiled executable (a JAR file) is available [on GitHub](https://github.com/oktadeveloper/okta-aws-cli-assume-role/releases).