Rails 5.0 - How to implement in-place editing without using best_in_place gem

I'm building an Events site using RoR which I've just upgraded to v5.0.1 (not moving to 5.1 just yet). My events show page has a comments section at the foot of the page which, so far, only has a create and delete functionality.
I want to add an Edit/Update function to comments so only the user who created the comment can edit the comment if they see fit. I want them to be able to edit their comment whilst on the same page. I don't want to use best_in_place gem as this appears to be on the verge of being dormant having not been updated for 3 years.

I'm trying to implement these changes using remote: true & Ajax but I've never done this before and there doesn't appear to be a clear guide via the internet/SO. Here's my views & controller code -

_comment.html.erb

<% if user_signed_in?  %>
         <p><%= link_to "Edit", remote: true %></p>
                <p><%= link_to 'Delete', [comment.event, comment],
                                method: :delete,
                                class: "button",
                                data: { confirm: 'Are you sure?' } %></p>
         <% end %>

*Comments_controller.rb *

def update
    @comment.user = current_user

    respond_to do |format|
        if @comment.update
            format.html { redirect_to @comment, notice: 'Comment was successfully updated.' }
            format.js   { }
            format.json { render :show, status: :created, location: @comment }
        else
            format.html { render :new }
            format.json { render json: @comment.errors, status: :unprocessable_entity }
        end
    end
end

My understanding is that I need to include a .js.erb file in my views/comments folder to deal with this ( edit.js.erb ?) but what I'm not clear on is exactly what javascript code I need to include in order for this to work. Also, I don't think my controller code above seems right - should this go in the Edit action? Do I also need an Event#show action in my events controller as this is where it sits in the views?

Any assistance would be greatly appreciated.