[Adding variable descriptions]

README.md

@@ -1,6 +1,6 @@
 # aws-vpc-terraform
 
-![awsmag.com](./AWSMAG.com.png)
+![awsmag.com](https://raw.githubusercontent.com/awsmag/terraform-aws-vpc/master/AWSMAG.com.png)
 
 Terraform module to create a vpc with public and private subnets across multiple availability zones along with internet gateway and NAT gateway.
 

variables.tf

@@ -1,16 +1,27 @@
 
-variable "region" {}
+variable "region" {
+  description = "The region in which you would like to create a VPC"
+  nullable = false
+}
 
-variable "cidr_block" {}
+variable "cidr_block" {
+  description = "the primary CIDR block for the VPC"
+  nullable = false
+}
 
 variable "public_subnet_cidr" {
+  description = "The list of CIDR blocks for public subnet"
   type = list(string)
+  nullable = false
 }
 
 variable "private_subnet_cidr" {
+  description = "The list of CIDR blocks for private subnet"
   type = list(string)
+  nullable = false
 }
 
 variable "namespace" {
   default = "tf-generated-vpc"
+  nullable = false
 }