add user restriction

server/src/app/models/knowledge.py

@@ -1,8 +1,17 @@
 from sqlmodel import Field, SQLModel, Relationship
+from pydantic import BaseModel
+from src.app.models.user import User
 
 class Knowledge(SQLModel, table=True):
     id: int | None = Field(default=None, primary_key=True)
     content: str = Field(index=True)
     uri: str = Field(index=True)
 
-    questions: list["Question"] = Relationship(back_populates="knowledge", cascade_delete=True) # type: ignore
+    questions: list["Question"] = Relationship(back_populates="knowledge", cascade_delete=True) # type: ignore
+
+    user_id: int | None = Field(default=None, foreign_key="user.id", ondelete="CASCADE")
+    user: User | None =  Relationship(back_populates="knowledges")
+
+class KnowledgeCreate(BaseModel):
+    content: str
+    uri:str