[Vuejs]-Overlay on hover in vue.js

You don’t need to use js(vue) events. Do it with plain css, like in example you linked to.

Go with this template:

<div v-for="item in filteredPeople" v-bind:key="item.id" class="list-complete-item">
    <router-link :to="'/'+item.link">
        <img class="list-complete-img" :src="'http://placehold.it/400x300?text='+item.id" alt>
        <div class="overlay">
            <div class="text">{{ item.hovertext }}</div>
        </div>
    </router-link>
</div>

And style it up:

.list-complete-item {
    width: 400px;
    height: 300px;
    display: inline-block;
}
.list-complete-item a {
    display: inline-block;
    position: relative;
    width: 400px;
    height: 300px;
}
.list-complete-item a .image {
    display: block;
    width: 100%;
    height: auto;
}
.list-complete-item a .overlay {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    height: 100%;
    width: 100%;
    opacity: 0;
    transition: .5s ease;
    background-color: #008CBA;
}
.list-complete-item a:hover .overlay {
    opacity: 1;
}
.list-complete-item a .text {
    color: white;
    font-size: 20px;
    position: absolute;
    top: 50%;
    left: 50%;
    -webkit-transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
    text-align: center;
}

And the final result: