Polish the WSGI example and its docs.

Clarify in the tutorial that the URL slug for each kind is derived from
the model class name (so ``DwarfPlanet`` is reached at ``/dwarfplanets``,
no underscore), and that the SQLite database persists across runs.

Seed the database via a plain SQLAlchemy ``Session`` rather than spinning
up a throwaway ``falcon_sqla.Manager`` just to use its ``session_scope``
inside ``init_engine``.

Author: vytas7

docs/examples.rst

@@ -33,6 +33,11 @@ Perform an API request::
 
     $ curl http://localhost:8000/stars
 
+Each collection is exposed under a URL slug derived from its model class name
+lower-cased with a trailing ``s``; ``DwarfPlanet`` is therefore reached at
+``/dwarfplanets`` (no underscore), alongside ``/stars``, ``/planets`` and
+``/satellites``.
+
 The astute reader will notice that minor dwarf planets and lesser known
 satellites are missing from the responses.
 
@@ -49,7 +54,11 @@ manager to add records; for instance, let's add
 ...         name='eris', mass=1.6466e22, radius=1163.0, distance=1.01237e10))
 ...
 
-Let's run the server again. We can also add celestial bodies via the API; we'll
+Let's run the server again. The SQLite file lives next to the script and
+persists across runs, so Eris is still in the database from the previous
+step.
+
+We can also add celestial bodies via the API; we'll
 use the popular Python ``requests`` client. Open a separate interpreter in
 parallel to the API:
 

examples/solar_sync.py

@@ -21,6 +21,7 @@
 from sqlalchemy.orm import mapped_column
 from sqlalchemy.orm import MappedAsDataclass
 from sqlalchemy.orm import relationship
+from sqlalchemy.orm import Session
 
 import falcon_sqla
 
@@ -160,14 +161,15 @@ def _sqlite_enable_foreign_keys(dbapi_connection, _) -> None:
         Base.metadata.create_all(engine)
 
         # Seed with data from solar_system.json
-        with falcon_sqla.Manager(engine).session_scope() as session:
+        with Session(engine) as session:
             data = json.loads(DATA_PATH.read_text())
             for kind, items in data.items():
                 for item in items:
                     item = {**item, 'name': item['name'].lower()}
                     if 'primary' in item:
                         item['primary'] = item['primary'].lower()
                     session.add(_KINDS[kind](**item))
+            session.commit()
     else:
         print(f'Using existing database: {engine.url}')