Add scope to filter SDG relations by review status

spec/models/sdg/relatable_spec.rb

@@ -170,4 +170,23 @@ describe SDG::Relatable do
       expect(relatable.class.by_target(target.code)).to be_empty
     end
   end
+
+  describe ".pending_sdg_review" do
+    let!(:relatable) { create(:proposal) }
+
+    it "returns records not reviewed yet" do
+      create(:sdg_review, relatable: create(:proposal))
+
+      expect(relatable.class.pending_sdg_review).to match_array [relatable]
+    end
+  end
+
+  describe ".sdg_reviewed" do
+    let!(:relatable) { create(:proposal) }
+    let!(:reviewed_relatable) { create(:sdg_review, relatable: create(:proposal)).relatable }
+
+    it "returns records already reviewed" do
+      expect(relatable.class.sdg_reviewed).to match_array [reviewed_relatable]
+    end
+  end
 end