Update README.md for Hacktoberfest (#137)

Author: kylemh

README.md

@@ -1,4 +1,22 @@
-# operationcode_infra
+<div align="center">
+  <br />
+  <a href="https://operationcode.org">
+    <img
+      alt="Operation Code Hacktoberfest Banner"
+      src="https://operation-code-assets.s3.us-east-2.amazonaws.com/operation_code_hacktoberfest_2019.jpg"
+    >
+  </a>
+  <br />
+  <br />
+</div>
+
+# 🎃 Hacktoberfest 🎃
+
+[All the details you need](https://github.com/OperationCode/START_HERE/blob/master/README.md#-hacktoberfest-) before participating with us.
+
+<br />
+
+# Operation Code Infra
 Platform infrastructure for the Operation Code site.
 
 [![CircleCI](https://circleci.com/gh/OperationCode/operationcode_infra/tree/master.svg?style=svg)](https://circleci.com/gh/OperationCode/operationcode_infra/tree/master)