Update README.md

Author: virgofx

README.md

@@ -23,11 +23,37 @@ Operating Systems Supported:
 #### 3. Git Subtree
 
 
+## Variables
+
+```
+AWS_CODE_DEPLOY_KEY
+AWS_CODE_DEPLOY_SECRET
+AWS_CODE_DEPLOY_REGION
+
+AWS_CODE_DEPLOY_APPLICATION_NAME
+
+AWS_CODE_DEPLOY_DEPLOYMENT_GROUP_NAME
+AWS_CODE_DEPLOY_DEPLOYMENT_CONFIG_NAME
+
+AWS_CODE_DEPLOY_APP_SOURCE
+
+AWS_CODE_DEPLOY_S3_BUCKET
+AWS_CODE_DEPLOY_S3_KEY_PREFIX
+AWS_CODE_DEPLOY_S3_FILENAME
+AWS_CODE_DEPLOY_S3_LIMIT_BUCKET_FILES
+AWS_CODE_DEPLOY_S3_SSE
+
+AWS_CODE_DEPLOY_REVISION_DESCRIPTION
+```
+
+
 ## Usage
 
 
 
 
+
+
 ## AWS Code Deploy Workflow
 
 To deploy an application with AWS Code Deploy, the Wercker step follow this steps :