{% if not request.user in user.followers.all %}
<form action="/follow/" method="post">
    {% csrf_token %}
    <input type="hidden" name="user" value="{{ user.username }}"></input>
    <input type="submit" value="Follow"></input>
</form>
{% else %}
<form action="/unfollow/" method="post">
    {% csrf_token %}
    <input type="hidden" name="user" value="{{ user.username }}"></input>
    <input type="submit" value="Unfollow"></input>
</form>
{% endif %}