Feat: add put for student and fix fixture around database

backend/api/main.py

@@ -86,3 +86,26 @@ async def post_student(item: StudentModel):
     conn.commit()
 
     return student.to_dict()
+
+
+@app.put(
+    "/students/{student_id}",
+    status_code=status.HTTP_200_OK,
+    response_model=StudentModel,
+)
+async def put_student(student_id, item: StudentModel):
+    tribe_name = item.tribe_name
+    try:
+        tribe = tribe_repo.get(tribe_name)
+    except TribeRepositoryError:
+        return JSONResponse(
+            status_code=status.HTTP_409_CONFLICT,
+            content=f"The tribe {tribe_name} does not exists. You can't add a student in it.",
+        )
+
+    student = Student(name=item.name, tribe=tribe, id=student_id)
+
+    student_repo.update(student)
+    conn.commit()
+
+    return student.to_dict()