add: declarative search index

src/models.py

@@ -1,4 +1,4 @@
-from sqlalchemy import Column, Integer, String, DateTime
+from sqlalchemy import Column, Computed, DateTime, Index, Integer, String
 
 # we might need vector concat later, then we'll have to bring in sqlalchemy_utils
 # https://sqlalchemy-utils.readthedocs.io/en/latest/_modules/sqlalchemy_utils/types/ts_vector.html
@@ -47,4 +47,11 @@ class ItemCreate(ItemBase):
 
 class Item(ItemBase):
 
-    geodata_search_ts = Column(TSVECTOR)
+    geodata_search_ts = Column(
+        TSVECTOR,
+        Computed("to_tsvector('russian', geodata.description)", persisted=True),
+    )
+
+    __table_args__ = Index(
+        "geodata_search_idx", geodata_search_ts, postgresql_using="gin"
+    )