Update Dockerfile to correctly install requirements in dev

Dockerfile

-FROM jupyter/datascience-notebook:hub-3.1.1
+FROM jupyter/scipy-notebook:hub-1.5.0
 
 # Install from APT repository
 USER root
 RUN apt-get update -y
-RUN apt-get install -y git
+RUN apt-get install -y git libpq-dev gcc
+
+# Set working directory
+WORKDIR /usr/src/app
 
 # Install basics
 USER jovyan
 RUN pip3 install --upgrade pip
+COPY .env .env
 
-# RUN pip3 install --upgrade pip
-RUN pip install jupyter-server-proxy==4.0.0
-RUN pip install jupyterlab-git==0.42.0
-RUN pip install jupyterlab-gitlab==3.0.0
+# Install python packages
+COPY requirements.txt requirements.txt
+RUN pip install --no-cache-dir -r requirements.txt
+ENV IPYTHONDIR /usr/src/app/ipython/
+WORKDIR /usr/src/app/ipython/profile_default/startup/
+COPY python_startup/ ./
+WORKDIR /home/