added example of how to call this module

Author: ntmspavan

README.md

@@ -1 +1,13 @@
-# terraform-aws-security-group
+# terraform-aws-security-group
+# Sample way of calling this module
+```
+module "sg" {
+  source  = "git@github.com:devops-made-easy/terraform-aws-security-group.git"
+  version = "0.0.1"
+  name                       = "DEVOPS-MADES-EASY-SG"
+  description                = "DEVOPS-MADES-EASY description"
+  vpc_id                     = "vpc-xxxx"
+  ingress_rules              = [{"description": "description for ingress", "from_port": 443, "to_port": 443, "protocol": "HTTPS", "cidr_block": ["0.0.0.0/0"]}]
+  egress_rules               = [{"description": "description for engress", "from_port": 443, "to_port": 443, "protocol": "HTTPS", "cidr_block": ["0.0.0.0/0"]}]
+}
+```