Backend/demoserver: Move out of directory again because of docker build context problems.

Backend/demoserver/Dockerfile → Backend/Dockerfile

@@ -4,14 +4,14 @@ ENV FLASK_APP app.py
 ENV FLASK_DEBUG true
 EXPOSE 80
 
-COPY ../requirements.txt /requirements.txt
+COPY ./requirements.txt /requirements.txt
 RUN pip install -r requirements.txt
 
-COPY ../app.py /app.py
-COPY ../settings.py /settings.py
-COPY ../security.py /security.py
-COPY ../signups.py /signups.py
-COPY ../validation.py /validation.py
+COPY ./app.py /app.py
+COPY ./settings.py /settings.py
+COPY ./security.py /security.py
+COPY ./signups.py /signups.py
+COPY ./validation.py /validation.py
 
 COPY ./demo_server.py /demo_server.py