Make result's data a dictionary.

debexpo/model/plugin_results.py

@@ -33,6 +33,7 @@ Holds plugin_results table model.
 
 from sqlalchemy import orm
 import sqlalchemy as sa
+from sqlalchemy.orm.collections import attribute_mapped_collection
 
 from debexpo.model import meta, OrmObject
 from debexpo.model.package_versions import PackageVersion
@@ -67,13 +68,16 @@ plugin_result_mapper = orm.mapper(PluginResult,
     polymorphic_identity = 'plugin_results',
     properties = {
         'package_version' : orm.relation(PackageVersion,
-                                         backref='plugin_results'),
+                                         backref='plugin_results',),
         }
     )
 
 plugin_result_data_mapper = orm.mapper(PluginResultData,
     t_plugin_result_data,
     properties = {
-        'plugin_result' : orm.relation(PluginResult, backref='result_data'),
+        'plugin_result' : orm.relation(PluginResult,
+            backref = orm.backref('data',
+                collection_class=attribute_mapped_collection('key'))
+            )
     }
 )