Error while adding a Dockerfile to install more dependencies

[AwaishK]

I am trying to install git and few other dependencies for that I have created Dockerfile in the airflow-tutorial directory. and added below lines in the file.

RUN apt-get update && \
    apt-get install -y git

RUN pip install dataclasses

then trying to build it with docker-compose up --build

but it keep failing and error is
ModuleNotFoundError: No module named 'dataclasses'

it works perfectly fine without my Dockerfile, Can any body please help me solve this issue?