feat: add database connection with modified endpoints

dependencies/models.py

@@ -0,0 +1,9 @@
+from sqlalchemy import Column, Integer, String
+from dependencies.database import Base
+
+class UrlMapping(Base):
+    __tablename__ = "url_mapping"
+
+    id = Column(Integer, primary_key=True, index=True)
+    url = Column(String, nullable=False)
+    shortcode = Column(String, index=True, unique=True, nullable=False)