Initial commit, added all backend files

Dockerfile

@@ -0,0 +1,19 @@
+FROM google/dart:2.7
+
+WORKDIR /app
+
+# Get Dart dependencies
+RUN mkdir -p /pub-cache
+ENV PUB_CACHE=/pub-cache
+ENV PATH="${PATH}:/pub-cache/bin"
+RUN pub global activate webdev
+ADD pubspec.* /app/
+RUN pub get
+RUN pub get --offline
+
+RUN apt update && apt install ruby-sass ruby-dev build-essential -y
+RUN gem install sass-listen
+
+ADD . /app/
+
+CMD ["./start.sh"]