diff --git a/backend/app/app/db/init_db.py b/backend/app/app/db/init_db.py
index 9c84b2d..cca368a 100644
--- a/backend/app/app/db/init_db.py
+++ b/backend/app/app/db/init_db.py
@@ -36,7 +36,6 @@ def init_db(session: Session) -> None:
                 is_active=False,
             )
             user = User.create(session, user_in)
-            logging.debug(f"User {user.email} created")  # type: ignore
 
         with open("/app/app/db/item.csv", "r") as file:
             reader = csv.reader(file)
diff --git a/backend/app/app/worker.py b/backend/app/app/worker.py
index 8a6b4f6..ed8b217 100644
--- a/backend/app/app/worker.py
+++ b/backend/app/app/worker.py
@@ -7,6 +7,7 @@
 from typing import Union
 
 import gensim
+import numpy as np
 import pandas as pd
 from celery import Task
 from celery.utils.log import get_task_logger
@@ -17,7 +18,6 @@
 from rectools.dataset import Dataset
 from rectools.metrics import MAP, MeanInvUserFreq, Serendipity, calc_metrics
 from rectools.models import ImplicitALSWrapperModel
-from sklearn.model_selection import train_test_split
 from sqlmodel import Session, col, select
 
 from app import source
@@ -193,6 +193,28 @@ def byte_to_list_float(byte: bytes):
     return list(struct.unpack("f" * (len(byte) // 4), byte))
 
 
+def train_test_split(
+    df: DataFrame, test_size: float = 0.2, random_state: int = 32
+):
+    """
+    Split the dataset into train and test sets.
+
+    Args:
+        df (DataFrame): The dataset to split.
+        test_size (float): The size of the test set.
+        random_state (int): The random state for reproducibility.
+
+    Returns:
+        tuple: A tuple of train and test sets.
+    """
+    np.random.seed(random_state)
+    shuffled_indices = np.random.permutation(len(df))
+    test_set_size = int(len(df) * test_size)
+    test_indices = shuffled_indices[:test_set_size]
+    train_indices = shuffled_indices[test_set_size:]
+    return df.iloc[train_indices], df.iloc[test_indices]
+
+
 @celery_app.task(
     acks_late=True,
     base=DatabaseTask,
diff --git a/backend/backend.dockerfile b/backend/backend.dockerfile
index f3c114e..3a81b6c 100644
--- a/backend/backend.dockerfile
+++ b/backend/backend.dockerfile
@@ -10,8 +10,7 @@ COPY ./app/pyproject.toml ./app/poetry.lock* /app/
 
 # Allow installing dev dependencies to run tests
 ARG INSTALL_DEV=false
-RUN if [ $INSTALL_DEV == 'true' ] ; then poetry install --no-root ; else poetry install --no-root --only main ; fi
-RUN poetry run python -m pip install --no-use-pep517 rectools[lightfm]
+RUN sh -c "if [ '$INSTALL_DEV' == 'true' ] ; then poetry install --no-root ; else poetry install --no-root ; fi"
 
 COPY ./app /app
 
diff --git a/backend/celeryworker.dockerfile b/backend/celeryworker.dockerfile
index 35c6ac1..0aa7e67 100644
--- a/backend/celeryworker.dockerfile
+++ b/backend/celeryworker.dockerfile
@@ -11,8 +11,7 @@ COPY ./app/pyproject.toml ./app/poetry.lock* /app/
 
 # Allow installing dev dependencies to run tests
 ARG INSTALL_DEV=false
-RUN if [ $INSTALL_DEV == 'true' ] ; then poetry install --no-root ; else poetry install --no-root --only main ; fi
-RUN poetry run python -m pip install --no-use-pep517 rectools[lightfm]
+RUN sh -c "if [ '$INSTALL_DEV' == 'true' ] ; then poetry install --no-root ; else poetry install --no-root ; fi"
 
 ENV C_FORCE_ROOT=1