Add availability zone to instance ressource module (#35)

modules/db_instance/main.tf

@@ -42,6 +42,7 @@ resource "aws_db_instance" "this" {
   db_subnet_group_name   = "${var.db_subnet_group_name}"
   parameter_group_name   = "${var.parameter_group_name}"
 
+  availability_zone   = "${var.availability_zone}"
   multi_az            = "${var.multi_az}"
   iops                = "${var.iops}"
   publicly_accessible = "${var.publicly_accessible}"

modules/db_instance/variables.tf

@@ -89,6 +89,11 @@ variable "parameter_group_name" {
   default     = ""
 }
 
+variable "availability_zone" {
+  description = "The Availability Zone of the RDS instance"
+  default     = ""
+}
+
 variable "multi_az" {
   description = "Specifies if the RDS instance is multi-AZ"
   default     = false