Set instance key_name to value of new variable

ntools/one-m/aws/main.tf

@@ -13,7 +13,7 @@ resource "aws_instance" "instance" {
     Name        = "BigchainDB_node"
   }
   ebs_optimized = true
-  key_name      = "bigchaindb"
+  key_name      = "${var.ssh_key_name}"
   vpc_security_group_ids = ["${aws_security_group.node_sg1.id}"]
   root_block_device = {
     volume_type = "gp2"

ntools/one-m/aws/variables.tf

@@ -13,3 +13,7 @@ variable "root_storage_in_GiB" {
 variable "DB_storage_in_GiB" {
   default = 30
 }
+
+variable "ssh_key_name" {
+  # No default. Ask as needed.
+}