Fix missing letter in "terraform"

README.md

@@ -59,7 +59,7 @@ This deployment creates a firewall group, adds rules to this group, and assigns
 
 ```
 resource "vultr_firewall_group" "my_firewall_grp" {
-    description = "mumble-fw-deployed-by-terrafor"
+    description = "mumble-fw-deployed-by-terraform"
 }
 ```