add copy notification

src/components/ArticleFooter.vue

 <template>
   <div class="article_footer">
-    
-      <v-btn v-if="!webShareApiSupported || $vuetify.breakpoint.mdAndUp" x-small depressed class="toolbar-button" rounded tabindex="0" @click="copy_link">
-        <v-icon small>link</v-icon> <span class = "button-text">Kopier lenke</span>
+     <v-snackbar center left light 
+                 v-model='copy_popup'
+                 timeout="2000">
+         
+        <span class="text-center">Kopiert til utklippstavla</span>
+              <template v-slot:action="{ attrs }">
+          <v-btn
+            color="primary"
+            text
+            v-bind="attrs"
+            @click="copy_popup = false"
+          >
+            <v-icon>close</v-icon>
+          </v-btn>
+        </template>
+      </v-snackbar>
+
+      <v-btn v-if="!webShareApiSupported || $vuetify.breakpoint.mdAndUp"
+             x-small depressed class="toolbar-button" rounded tabindex="0" @click="copy_link">
+        <v-icon small>link</v-icon><span class = "button-text">Kopier lenke</span>
       </v-btn>
 
+
       <v-btn v-if="webShareApiSupported" depressed x-small class="toolbar-button" rounded tabindex="0" @click="shareViaWebShare">
         <v-icon x-small>share</v-icon><span class = "button-text">Del ordet</span>
       </v-btn>
@@ -52,6 +70,7 @@ export default {
   },
   data: function() {
     return {
+      copy_popup: false,
       citation_dialog: false
     }
 
@@ -85,12 +104,15 @@ export default {
     },
     copy_link() {
       navigator.clipboard.writeText(this.create_link());
+      this.copy_popup = true
     },
 
     copy_citation() {
+      
       let citation = document.getElementById("citation").textContent;
       navigator.clipboard.writeText(citation)
       this.citation_dialog = false
+      this.copy_popup = true
     },
 
     close_citation_dialog() {