<form>
            <ol>
              <li class="inputQuestion" v-bind:class="{ 'error': $v.user.username.$error }">
                <label>Username:</label>
                <input v-model.trim="user.username" @input="$v.user.username.$touch()" />
              </li>
              <li class="inputQuestion" v-bind:class="{ 'error': $v.user.password.$error }">
                <label>Password:</label>
                <input v-model.trim="user.password" @input="$v.user.password.$touch()" />
              </li>

              <li class="submission">
                <button @click.prevent="submitForm" :disabled="$v.form.valid()">Sign In</button>
              </li>
            </ol>
          </form>