Resolve "Create eggnog card"

Closes #71 Closes #108 Closes #106

backend/metagenedb/apps/catalog/serializers/function.py

 from rest_framework import serializers
-from metagenedb.apps.catalog.models import EggNOG, Function, KeggOrthology
+from metagenedb.apps.catalog.models import (
+    EggNOG, EggNogFunctionalCategory, Function, KeggOrthology
+)
 
+from .asymetricslugrelatedfield import AsymetricSlugRelatedField
 from .bulk_list import BulkListSerializer
 
 
@@ -24,7 +27,21 @@ class EggNOGListSerializer(BulkListSerializer):
         model = EggNOG
 
 
+class EggNogFunctionalCategorySerializer(serializers.ModelSerializer):
+
+    class Meta:
+        model = EggNogFunctionalCategory
+        fields = ('category_id', 'name', 'group')
+
+
 class EggNOGSerializer(serializers.ModelSerializer):
+    functional_categories = AsymetricSlugRelatedField.from_serializer(
+        EggNogFunctionalCategorySerializer,
+        queryset=EggNogFunctionalCategory.objects.all(),
+        slug_field='category_id',
+        many=True,
+        required=False,
+    )
 
     class Meta:
         model = EggNOG