chore: add terraform configuration for A-type DNS records.

Part of #1000

[skip ci]

Author: php-coder

infra/terraform/README.md

@@ -14,7 +14,12 @@
   ```console
   $ terraform import digitalocean_droplet.web <id>
   $ terraform import digitalocean_domain.site my-stamps.ru
+  $ terraform import digitalocean_record.www my-stamps.ru,<id>
+  $ terraform import digitalocean_record.no-www my-stamps.ru,<id>
   ```
+  The ids can be obtained by API:
+  - https://developers.digitalocean.com/documentation/v2/#list-all-droplets
+  - https://developers.digitalocean.com/documentation/v2/#list-all-domain-records
 * Plan and apply:
   ```console
   $ terraform plan -out terraform.tfplan

infra/terraform/my-stamps.tf

@@ -22,3 +22,17 @@ resource "digitalocean_droplet" "web" {
 resource "digitalocean_domain" "site" {
   name = "my-stamps.ru"
 }
+
+# https://www.terraform.io/docs/providers/do/r/record.html
+resource "digitalocean_record" "no-www" {
+  domain = digitalocean_domain.site.name
+  type   = "A"
+  name   = "@"
+  value  = digitalocean_droplet.web.ipv4_address
+}
+resource "digitalocean_record" "www" {
+  domain = digitalocean_domain.site.name
+  type   = "A"
+  name   = "www"
+  value  = digitalocean_droplet.web.ipv4_address
+}