button("hello", to: "/world")
#=> <form action="/world" class="button" method="post">
<input name="_csrf_token" value="">
<button type="submit">hello</button>
</form>
button("hello", to: "/world", method: "get", class: "btn")
#=> <form action="/world" class="btn" method="get">
<button type="submit">hello</button>
</form>