Support natures in lookup.

pokedex/db/tables.py

@@ -268,6 +268,7 @@ class Move(TableBase):
 
 class Nature(TableBase):
     __tablename__ = 'natures'
+    __singlename__ = 'nature'
     id = Column(Integer, primary_key=True, nullable=False)
     name = Column(Unicode(8), nullable=False)
     decreased_stat_id = Column(Integer, ForeignKey('stats.id'), nullable=False)

pokedex/lookup.py

@@ -60,6 +60,7 @@ class PokedexLookup(object):
             tables.Item,
             tables.Location,
             tables.Move,
+            tables.Nature,
             tables.Pokemon,
             tables.Type,
         )