prepared app for production (removed global variables, add flask-pymongo as db driver

dockerfiles/python-env/Dockerfile

@@ -1,26 +1,25 @@
-FROM ubuntu:16.04
+FROM ubuntu:18.04
 
 RUN apt-get update --fix-missing
 RUN apt-get install -y \
 vim \
 python3 \
 python3-pip \
-sshfs
+sshfs \
+curl
+
+RUN pip3 install --upgrade pip
 
 RUN pip3 install \
 	lxml \
 	pandas \
 	sklearn \
 	argparse \
+	pyyaml \
 	pathlib \
+	flask \
+	flask_cors \
 	pymongo \
-	flask
-
-RUN apt-get install -y \
-	curl
+	flask-pymongo
 
 ENV PYTHONIOENCODING UTF-8
-
-RUN pip3 install \
-	pyyaml \
-	flask_cors