moved info here

Author: Matt Bernier

USAGE.md

@@ -1 +1,11 @@
-- [Example Code](https://github.com/sendgrid/csharp-http-client/blob/master/Example/Example.cs)
+# Usage
+
+- [Example Code](https://github.com/sendgrid/csharp-http-client/blob/master/Example/Example.cs)
+
+## Environment Variables 
+
+You can do the following to create a .env file:
+
+```cp .env_example .env```
+
+Then, just add your API Key into your .env file.