Adds usage documentation

Author: rsclarke

README.md

@@ -1,2 +1,49 @@
 # terraform-cloudflare-no-email
-SPF, DKIM and DMARC records for zones with no MX entries.
+
+SPF, DKIM and DMARC records for zones which do not send email.
+
+This creates a `cloudflare_record` resource for SPF, DKIM and DMARC of the given `zone_id`.
+
+The SPF and DMARC policies are set to reject all and you must provide an email address for DMARC Aggregate and Failure reports, through the `dmarc_rua` and `dmarc_ruf` variables respectively.
+
+## Usage
+
+```terraform
+
+resource "cloudflare_zone" "example_com" {
+  zone = "example.com"
+}
+
+module {
+  source = "rsclarke/no-email/cloudflare"
+
+  zone_id   = cloudflare_zone.example_com.id
+  dmarc_rua = ["[email protected]"]
+  dmarc_ruf = ["[email protected]", "[email protected]"]
+}
+```
+
+## Requirements
+
+| Name | Version |
+|------|---------|
+| terraform | `~> 0.14.0` |
+| cloudflare | `>= 2.0` |
+
+## Providers
+
+| Name | Version |
+|------|---------|
+| cloudflare | `>= 2.0` |
+
+## Inputs
+
+| Name | Description | Type | Required |
+|------|-------------|------|:--------:|
+| zone_id | Cloudflare Zone ID | `string` | yes |
+| dmarc_rua | Email addresses for DMARC Aggregate reports (excluding `mailto:`), at least one and contains the `@` symbol. | `list(string)` | yes |
+| dmarc_rua | Email addresses for DMARC Failure (or Forensic) reports (excluding `mailto:`), at least one and contains the `@` symbol. | `list(string)` | yes |
+
+## Outputs
+
+This module does not expose any ouputs.