Add field published_on and title to Issue

/refs #16

Add field published_on and title to Issue and display both fields.

kontor-api/src/db/models/comic.py

@@ -95,6 +95,8 @@ class StoryArc(Base, BaseMixin):
 class Issue(Base, BaseMixin):
     __tablename__ = "issue"
     issue_number = Column(String)
+    title = Column(String, nullable=True)
+    published_on: Mapped[datetime] = mapped_column(nullable=True)
     in_stock = Column(Boolean)
     is_read = Column(Boolean)
     comic_id = Column(String, ForeignKey("comic.id"), nullable=False)