Add existing open group creators as members

Add a DB migration to add the creators of existing open groups as
members of those groups.

h/migrations/versions/146179fa8d5e_add_open_group_creators_as_members.py

@@ -0,0 +1,82 @@
+"""Add open group creators as members."""
+
+import enum
+import logging
+from collections import defaultdict
+
+from alembic import op
+from sqlalchemy import Column, Enum, ForeignKey, Integer, select
+from sqlalchemy.orm import declarative_base, relationship, sessionmaker
+
+revision = "146179fa8d5e"
+down_revision = "ecf91905c143"
+
+
+log = logging.getLogger(__name__)
+
+
+Base = declarative_base()
+
+
+class JoinableBy(enum.Enum):
+    pass
+
+
+class ReadableBy(enum.Enum):
+    world = "world"
+
+
+class WriteableBy(enum.Enum):
+    members = "members"
+
+
+class User(Base):
+    __tablename__ = "user"
+    id = Column(Integer, primary_key=True)
+
+
+class Group(Base):
+    __tablename__ = "group"
+    id = Column(Integer, primary_key=True)
+    creator_id = Column(Integer, ForeignKey("user.id"))
+    creator = relationship("User")
+    joinable_by = Column(Enum(JoinableBy, name="group_joinable_by"))
+    readable_by = Column(Enum(ReadableBy, name="group_readable_by"))
+    writeable_by = Column(Enum(WriteableBy, name="group_writeable_by"))
+    members = relationship("User", secondary="user_group")
+
+
+class UserGroup(Base):
+    __tablename__ = "user_group"
+    id = Column(Integer, primary_key=True)
+    user_id = Column("user_id", Integer, ForeignKey("user.id"))
+    group_id = Column(Integer, ForeignKey("group.id"))
+
+
+def upgrade():
+    db = sessionmaker()(bind=op.get_bind())
+
+    open_groups = db.scalars(
+        select(Group)
+        .where(Group.joinable_by == None)
+        .where(Group.readable_by == ReadableBy.world)
+        .where(Group.writeable_by == WriteableBy.members)
+    )
+
+    results = defaultdict(lambda: 0)
+
+    for group in open_groups:
+        if not group.creator:
+            results["no_creator"] += 1
+        elif group.creator in group.members:
+            results["already_member"] += 1
+        else:
+            group.members.append(group.creator)
+            results["appended"] += 1
+
+    db.commit()
+    log.info(dict(results))
+
+
+def downgrade():
+    pass