Merge pull request #42 from dhsrocha/master

Added example file, updated .gitignore and README.

Author: Matt Bernier

.gitignore

@@ -14,3 +14,6 @@ CSharpHTTPClient/packages/
 CSharpHTTPClient/CSharpHTTPClient.sln.VisualState.xml
 *.PublicKey
 *.pfx
+
+# Environment files
+.env/*.*

Example/.env_sample

@@ -0,0 +1 @@
+export SENDGRID_API_KEY=''

README.md

@@ -85,12 +85,20 @@ Console.WriteLine(response.StatusCode);
 Console.WriteLine(response.Body.ReadAsStringAsync().Result);
 Console.WriteLine(response.Headers.ToString());
 ```
-
 <a name="usage"></a>
 # 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.
+
+
 <a name="roadmap"></a>
 # Roadmap
 
@@ -121,4 +129,4 @@ csharp-http-client is guided and supported by the SendGrid [Developer Experience
 csharp-http-client is maintained and funded by SendGrid, Inc. The names and logos for csharp-http-client are trademarks of SendGrid, Inc.
 
 # License
-[The MIT License (MIT)](LICENSE.txt)
+[The MIT License (MIT)](LICENSE.txt)