Merge pull request #11 from tinpee/master

Use explicitly python 3.5 image and automatically upgrade pip

Dockerfile

@@ -1,9 +1,10 @@
-FROM python
+FROM python:3.5
 MAINTAINER Tinpee <tinpee.dev@gmail.com>
 
 ADD . /src
 WORKDIR /src
-RUN pip install flask gunicorn
+RUN pip install --upgrade pip \
+    && pip install flask gunicorn
 
 COPY entrypoint.sh /
 RUN chmod +x /entrypoint.sh