Merge pull request #4216 from gkze/master

Add terraform completion

plugins/terraform/README.md

+## atom
+
+Plugin for Terraform, a tool from Hashicorp for managing infrastructure safely and efficiently.
+
+### Requirements
+
+ * [Terraform](https://terraform.io/)
+
+### Usage
+
+ * Type `terraform` into your prompt and hit `TAB` to see available completion options