Add Settings page.

src/components/settings/settings.js

+import StyleSwitcher from '../style_switcher/style_switcher.vue'
+
+const settings = {
+  components: {
+    StyleSwitcher
+  }
+}
+
+export default settings

src/components/settings/settings.vue

+<template>
+  <div class="settings panel panel-default base00-background">
+    <div class="panel-heading base01-background base04">
+      Settings
+    </div>
+    <div class="panel-body">
+      <div class="setting-item">
+        <h2>Theme</h2>
+        <style-switcher></style-switcher>
+      </div>
+    </div>
+  </div>
+</template>
+
+<script src="./settings.js">
+</script>
+
+<style>
+ .setting-item {
+   margin: 1em
+ }
+</style>