Fix exception for NIP-05 JSON of "_" with relay configured

spec/requests/well_known_spec.rb

@@ -75,6 +75,19 @@ RSpec.describe "Well-known URLs", type: :request do
         expect(res["names"]["_"]).to eq(Setting.nostr_public_key)
       end
 
+      context "with relay configured" do
+        before do
+          Setting.nostr_relay_url = "wss://nostr.kosmos.org"
+        end
+
+        it "returns the pubkey and relay" do
+          get "/.well-known/nostr.json?name=_"
+          res = JSON.parse(response.body)
+          expect(res["relays"]["_"].length).to eq(1)
+          expect(res["relays"]["_"].first).to eq("wss://nostr.kosmos.org")
+        end
+      end
+
       context "nostr service integration not enabled" do
         before do
           Setting.nostr_enabled = false