allow use of custom derivation path, and add way to increment derivation for existing

src/views/StartView.vue

@@ -10,30 +10,46 @@
 
     <div class="mt-8">
       <p class="text-center text-xl mb-4 font-light">
-        Do you already have an identity to import?
+        Do you have an identity to import?
       </p>
       <a
         @click="onClickYes()"
-        class="block w-full text-center text-lg font-bold uppercase bg-blue-600 text-white px-2 py-3 rounded-md mb-2"
+        class="block w-full text-center text-lg uppercase bg-blue-600 text-white px-2 py-3 rounded-md"
       >
         No
       </a>
       <a
         @click="onClickNo()"
-        class="block w-full text-center text-md uppercase bg-slate-500 text-white px-1.5 py-2 rounded-md"
-        >Yes</a
+        class="block w-full text-center text-md uppercase bg-slate-500 text-white px-1.5 py-2 rounded-md mt-2"
       >
+        Yes
+      </a>
+      <a
+        v-if="numAccounts > 0"
+        @click="onClickDerive()"
+        class="block w-full text-center text-md uppercase bg-slate-500 text-white px-1.5 py-2 rounded-md mt-2"
+      >
+        Derive from Existing Account
+      </a>
     </div>
   </section>
 </template>
 
 <script lang="ts">
 import { Component, Vue } from "vue-facing-decorator";
+import { accountsDB } from "@/db";
 
 @Component({
   components: {},
 })
 export default class StartView extends Vue {
+  numAccounts = 0;
+
+  async mounted() {
+    await accountsDB.open();
+    this.numAccounts = await accountsDB.accounts.count();
+  }
+
   public onClickYes() {
     this.$router.push({ name: "new-identifier" });
   }
@@ -41,5 +57,9 @@ export default class StartView extends Vue {
   public onClickNo() {
     this.$router.push({ name: "import-account" });
   }
+
+  public onClickDerive() {
+    this.$router.push({ name: "import-derive" });
+  }
 }
 </script>