Add comparison with previous month

app/assets/javascripts/application.js.erb

@@ -40,4 +40,5 @@ $(document).on('ready turbolinks:load', function(){
       }
     }, 3000);
   <% end %>
+  $('[data-toggle="tooltip"]').tooltip();
 });

app/controllers/transactions_controller.rb

@@ -128,6 +128,13 @@ def groupby_filter
         .group('categories.id')
         .order('_debit')
       @categorygroup = true
+      if @d.month == Time.zone.now.month
+        @prev_month_amount = current_user.transactions
+          .where('transactions.date between ? and ?', 1.month.ago.beginning_of_month, 1.month.ago)
+          .joins(:category)
+          .group('categories.name')
+          .sum(:amount)
+      end
       @grouped = true
     else
       @transactions = @transactions.order('date, memo')

app/views/transactions/_categorygroup.html.erb

@@ -6,6 +6,7 @@
         <th scope="col">Categoria</th>
         <th scope="col">Entrada</th>
         <th scope="col">Saida</th>
+        <th scope="col" data-toggle="tooltip" data-placement="top" title="Comparação com mesmo dia do mes anterior: (<%= l(1.month.ago, format: '%d/%m') %>)">Mês Anterior</th>
       </tr> 
     </thead>
     <tbody>
@@ -26,6 +27,9 @@
             <% end %>
             </span>
           </td>
+          <td>
+            <%= @prev_month_amount[t.category_name] if @prev_month_amount && @prev_month_amount[t.category_name] %>
+          </td>
         </tr>
       <% end %>
     </tbody>

db/schema.rb

@@ -81,7 +81,6 @@
     t.string "confirmation_token"
     t.datetime "confirmed_at"
     t.datetime "confirmation_sent_at"
-    t.boolean "admin", default: false
     t.index ["confirmation_token"], name: "index_users_on_confirmation_token", unique: true
     t.index ["email"], name: "index_users_on_email", unique: true
     t.index ["invitation_token"], name: "index_users_on_invitation_token", unique: true