App.vue to use dark theme provided by Vuetify.

App.vue

<template>
  <v-app id="app" dark>    
    <v-toolbar app fixed dense>
      <v-toolbar-title>
        Trackie<sup> pro</sup> 
        <span class="hidden-xs-only subheading"> - Your personal health tracker</span>
      </v-toolbar-title>
      <v-spacer></v-spacer>
      <v-btn v-if="hasCurrentUser" value="left" @click="signOut">
        <span class="mr-1">{{ currentUser.displayName }}</span>
        <v-icon>account_circle</v-icon>
      </v-btn>
    </v-toolbar>
    <v-content>
      <v-container fluid fill-height>
        <router-view></router-view>
      </v-container>
    </v-content>
    <v-footer app fixed>
      <p class="mt-3 ml-3">Trackie<sup> pro</sup></p> 
    </v-footer> 
  </v-app>
</template>
<script>
import { mapGetters, mapActions } from 'vuex'
export default {
  beforeCreate () {
    // Getting the current user directly from store
    const user = this.$store.getters.currentUser
    if (user) {
      this.$store.dispatch('fetchEntries')
    }
  },
  computed: {
    ...mapGetters([
      'currentUser',
      'hasCurrentUser'
    ])
  },
  methods: {
    ...mapActions([
      'signOut'
    ])
  }
}
</script>