Set JSONB columns to use none_as_null

By default, sqlalchemy will set the JSON value of null (the string
"null") in JSONB columns if you set them to None. I want it to set the
actual column to NULL, so they need to be defined with the none_as_null
argument set to True like this.

tildes/tildes/models/log/log.py

@@ -57,7 +57,7 @@ class BaseLog:
     @declared_attr
     def info(self) -> Column:
         """Return the info column."""
-        return Column(MutableDict.as_mutable(JSONB))
+        return Column(MutableDict.as_mutable(JSONB(none_as_null=True)))
 
     @declared_attr
     def user(self) -> Any:

tildes/tildes/models/scraper/scraper_result.py

@@ -28,7 +28,7 @@ class ScraperResult(DatabaseModel):
         index=True,
         server_default=text("NOW()"),
     )
-    data: Any = Column(JSONB)
+    data: Any = Column(JSONB(none_as_null=True))
 
     def __init__(self, url: str, scraper_type: ScraperType, data: Any) -> None:
         """Create a new ScraperResult."""

tildes/tildes/models/topic/topic.py

@@ -106,7 +106,9 @@ class Topic(DatabaseModel):
     _markdown: Optional[str] = deferred(Column("markdown", Text))
     rendered_html: Optional[str] = Column(Text)
     link: Optional[str] = Column(Text)
-    content_metadata: Dict[str, Any] = Column(MutableDict.as_mutable(JSONB))
+    content_metadata: Dict[str, Any] = Column(
+        MutableDict.as_mutable(JSONB(none_as_null=True))
+    )
     num_comments: int = Column(Integer, nullable=False, server_default="0", index=True)
     num_votes: int = Column(Integer, nullable=False, server_default="0", index=True)
     _tags: List[Ltree] = Column(

tildes/tildes/models/user/user.py

@@ -94,7 +94,7 @@ class User(DatabaseModel):
     open_new_tab_text: bool = Column(Boolean, nullable=False, server_default="false")
     theme_default: str = Column(Text)
     is_banned: bool = Column(Boolean, nullable=False, server_default="false")
-    permissions: Any = Column(JSONB)
+    permissions: Any = Column(JSONB(none_as_null=True))
     home_default_order: Optional[TopicSortOption] = Column(ENUM(TopicSortOption))
     home_default_period: Optional[str] = Column(Text)
     _filtered_topic_tags: List[Ltree] = Column(