Add roughtime.se to ecosystem.

Author: dansarie

ecosystem.json

@@ -24,6 +24,18 @@
         }
       ]
     },
+   {
+      "name": "roughtime.se",
+      "version": "IETF-Roughtime",
+      "publicKeyType": "ed25519",
+      "publicKey": "S3AzfZJ5CjSdkJ21ZJGbxqdYP/SoE8fXKY0+aicsehI=",
+      "addresses": [
+        {
+          "protocol": "udp",
+          "address": "roughtime.se:2002"
+        }
+      ]
+    },
     {
       "name": "time.txryan.com",
       "version": "Google-Roughtime",

ecosystem.json.go

@@ -49,6 +49,22 @@ and the DNS `TXT` record of `roughtime.int08h.com`:
 $ dig -t txt roughtime.int08h.com
 ```
 
+## roughtime.se
+
+[roughtime.se](https://roughtime.se) provides a stratum 1 Roughtime service. It
+runs the [roughtimed](https://github.com/dansarie/roughtimed) implementation.
+Hosting is provided by STUPI AB. The server is located in Stockholm, Sweden and
+is directly connected to atomic clocks that track the UTC timescale. The aim is
+for the server to be compatible with the
+[latest published IETF Roughtime draft](https://datatracker.ietf.org/doc/draft-ietf-ntp-roughtime/).
+The server is connected to high-availability power and network infrastructure in
+a datacenter, however no availability is guaranteed. The public key is available
+on the server's web site, and as a DNS TXT record:
+
+```
+dig TXT roughtime.se
+```
+
 ## time.txryan.com
 
 [time.txryan.com](https://time.txryan.com) runs on a stratum 2 NTP server.