Feat: update create stock logic usecase (#16)

* feat: update create stock logic in usecase

* test: add unit testing

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Co-authored-by: Eyo Chen <eyo.chen@amazingtalker.com>

Author: eyo-chen

src/adapters/base.py

@@ -19,3 +19,7 @@ class AbstractPortfolioRepository(ABC):
     @abstractmethod
     def update(self, portfolio: Portfolio) -> None:
         """Update portfolio in the repository"""
+
+    @abstractmethod
+    def get(self, user_id: int) -> Portfolio:
+        """Get Portfolio"""