The main obstacle to extract this partial was probably the paths for the
flag and unflag actions.
Now that we use Rails 5.1 `resolve` method to handle nested resources,
we can use `polymorphic_path`.
Also note the code is a bit ugly because comments render a divider. We
should probably use a CSS border instead.
Co-Authored-By: taitus <sebastia.roig@gmail.com>
