Add locale workaround for django-geojson to Dockerfile

Dockerfile

@@ -13,15 +13,24 @@ FROM debian:9
 
 # SYSTEM
 SHELL ["/bin/bash","-ex","-c"]
+ENV DEBIAN_FRONTEND noninteractive
 RUN apt-get update && apt-get install -y\
       build-essential\
+      locales\
       libgdal-dev\
       libpq-dev\
       python\
       python3-dev\
+      python3-pip\
       python3\
       rsync\
-      wget
+      virtualenv\
+      wget\
+ && echo "en_GB.UTF-8 UTF-8" > /etc/locale.gen\
+ && locale-gen en_GB.UTF-8\
+ && dpkg-reconfigure locales\
+ && /usr/sbin/update-locale LANG=en_GB.UTF-8
+ENV LC_ALL en_GB.UTF-8
 
 # COMPILE
 WORKDIR /build
@@ -39,8 +48,7 @@ RUN wget https://nodejs.org/dist/v7.10.0/node-v7.10.0-linux-x64.tar.gz\
 # PACKAGES
 WORKDIR /app
 COPY ./requirements.txt .
-RUN apt-get install python3-pip -y \
- && python3 -m pip install -r requirements.txt
+RUN python3 -m pip install -r requirements.txt
 
 # APP
 WORKDIR /app