fix deprecation warnings in spec (cc @nlalonde)

spec/serializers/category_detailed_serializer_spec.rb

@@ -7,24 +7,24 @@ describe CategoryDetailedSerializer do
     it "works for categories with no subcategories" do
       no_subcats = Fabricate(:category, topics_year: 10, topics_month: 5, topics_day: 2, posts_year: 13, posts_month: 7, posts_day: 3)
       json = CategoryDetailedSerializer.new(no_subcats, scope: Guardian.new, root: false).as_json
-      json[:topics_year].should ==  10
+      expect(json[:topics_year]).to eq(10)
-      json[:topics_month].should ==  5
+      expect(json[:topics_month]).to eq(5)
-      json[:topics_day].should ==  2
+      expect(json[:topics_day]).to eq(2)
-      json[:posts_year].should ==  13
+      expect(json[:posts_year]).to eq(13)
-      json[:posts_month].should ==  7
+      expect(json[:posts_month]).to eq(7)
-      json[:posts_day].should ==  3
+      expect(json[:posts_day]).to eq(3)
     end
 
     it "includes counts from subcategories" do
       parent = Fabricate(:category, topics_year: 10, topics_month: 5, topics_day: 2, posts_year: 13, posts_month: 7, posts_day: 3)
       subcategory = Fabricate(:category, parent_category_id: parent.id, topics_year: 1, topics_month: 1, topics_day: 1, posts_year: 1, posts_month: 1, posts_day: 1)
       json = CategoryDetailedSerializer.new(parent, scope: Guardian.new, root: false).as_json
-      json[:topics_year].should ==  11
+      expect(json[:topics_year]).to eq(11)
-      json[:topics_month].should ==  6
+      expect(json[:topics_month]).to eq(6)
-      json[:topics_day].should ==  3
+      expect(json[:topics_day]).to eq(3)
-      json[:posts_year].should ==  14
+      expect(json[:posts_year]).to eq(14)
-      json[:posts_month].should ==  8
+      expect(json[:posts_month]).to eq(8)
-      json[:posts_day].should ==  4
+      expect(json[:posts_day]).to eq(4)
     end
   end