Partially transitioned user data to MastoAPI. Added support for fetching

relationship data. Upgraded code to be more resilient to nulls caused by missing
data in either APIs

src/components/user_card/user_card.js

@@ -15,6 +15,9 @@ export default {
       betterShadow: this.$store.state.interface.browserSupport.cssFilter
     }
   },
+  created () {
+    this.$store.dispatch('fetchUserRelationship', this.user.id)
+  },
   computed: {
     classes () {
       return [{