Improve the Dockerfile

* reduce number of layers
* remove vim installation
* add LICENSE and README to .dockerignore
* don't cache with pip
* add EXPOSE directive

This set of changes reduces the image size by almost 100 Mb.

.dockerignore

@@ -5,4 +5,6 @@ db.sqlite
 .pytest_cache
 .vscode
 .DS_Store
-config
+config
+LICENSE
+README.md

Dockerfile

@@ -1,17 +1,14 @@
 FROM python:3.7
 
-RUN apt-get update
-
-RUN apt-get install -y vim
-
 WORKDIR /code
 
-COPY ./requirements.txt ./
-RUN pip3 install -r requirements.txt
-
-
+# copy everything into /code
 COPY . .
 
+# install dependencies
+RUN pip3 install --no-cache-dir -r requirements.txt
+
+EXPOSE 7777
+
 #gunicorn wsgi:app -b 0.0.0.0:7777 -w 2 --timeout 15 --log-level DEBUG
 CMD ["gunicorn","wsgi:app","-b","0.0.0.0:7777","-w","2","--timeout","15"]
-