feat: add terraform DNS docs

.gitignore

@@ -2,3 +2,4 @@
 /tags.*
 .direnv
 .terraform
+*.plan

docs/dns.md

@@ -1 +1,23 @@
 # Changing DNS entries
+
+### Initial setup
+
+Change into the terraform directory and initialize the terraform providers.
+
+```
+cd terraform
+cat ~/.config/triton/profiles.d/lev-1-pub_solar.json | grep keyId
+export TRITON_KEY_ID=
+
+terraform init
+```
+
+Plan your changes using:
+```
+terraform plan -out pub-solar-infra.plan
+```
+
+After verification, apply your changes with:
+```
+terraform apply "pub-solar-infra.plan"
+```