app/views/events/_month.html.erb
<tr>
<% calendar.first(7).each do |day,event| %>
<th><%= show_day_of_week(day, abbreviated) %></th>
<% end %>
</tr>
<% calendar.in_groups_of(7).each do |week| %>
<tr>
<% week.each do |date, has_events, this_month| %>
<% classes = [
!this_month ? 'calendar-day-out' : nil,
date == Date.today ? 'today' : nil,
date.day.to_s == params[:day] ? 'selected' : nil
] %>
<td class='calendar-day <%= classes.compact.join(' ') %>'>
<span>
<%= has_events ?
link_to(date.day, { action: 'events_by_date', year: date.year,
month: date.month, day: date.day,
category_id: @category_id },
remote: true, class: 'events-by-date')
: date.day
%>
</span>
</td>
<% end %>
</tr>
<% end %>