feat: add optional domain field (#120)

* feat: add optional domain field
closes #119

static/display.js

@@ -2,10 +2,26 @@ window.PageLnurlpPublic = {
   template: '#page-lnurlp-public',
   data() {
     return {
-      url: ''
+      url: '',
+      payLink: null
+    }
+  },
+  methods: {
+    setUrl(link_id, domain) {
+      this.url = `https://${domain || window.location.host}/lnurlp/${link_id}`
+    },
+    getPayLink() {
+      this.api
+        .request('GET', `/lnurlp/api/v1/links/public/${this.$route.params.id}`)
+        .then(res => {
+          this.payLink = res.data
+          this.setUrl(this.payLink.id, this.payLink.domain)
+        })
+        .catch(this.utils.notifyApiError)
     }
   },
   created() {
-    this.url = window.location.origin + '/lnurlp/' + this.$route.params.id
+    this.setUrl(this.$route.params.id)
+    this.getPayLink()
   }
 }