Using in_groups_of to create 3 posts per row layout.

index.html.erb

<div class="container">
    <div class="row">
        <div class="digg_pagination">
            <%= will_paginate @posts, :container => false %>
        </div>
    </div>
    <!-- Creates a loop of @posts.count / 3 arrays -->
    <% @posts.in_groups_of(3).each do |post_array| %>
    <div class="row">
        <!-- For each post in the array, give it a class of "col-4" which is 3 per row-->
        <% post_array.each do |post| %>
        <!-- If posts.count = 4, last array will be [post4, nil, nil] so if it's nil, don't do anything or you'll get an error-->
        <%  unless post.nil? %>
        <div class="col-4">
            <div class="card mb-3">
                <img class="card-img-top" src="<%= url_for post.optimized_image(post.thumbnail, 586, 180) %>" alt="Blog Post Image Card" />
                <div class="card-body">
                    <h5 class="card-title">
                        <%= link_to post.title, post %>
                    </h5>
                    <p class="card-text">
                        <%= post.body.to_plain_text.truncate_words(50) %>
                    </p>
                    <p class="card-text">
                        <small class="text-muted">
                            <%= post.updated_at.strftime("%A, %B %e, %Y") %> by
                            <%= post.user.username %> | <%= pluralize(post.views, "View") %> | 0 comments
                        </small>
                    </p>
                </div>
            </div>
        </div>
        <!-- Ends the "unless post.nil" block -->
        <% end %>
        <!-- Ends the "post_array.each" block -->
        <% end %>
    </div>
    <!-- Ends the "@posts.in_groups_of" block -->
    <% end %>
</div>