Installed yarn in docker

Author: Dorthu

Dockerfile

@@ -5,6 +5,20 @@ RUN apt-get update && apt-get install -y python3 python3-pip build-essential
 RUN pip3 install -r requirements.txt
 RUN gem install --no-ri --no-rdoc fpm
 
+# I stole this from the linodemanager-builder to get yarn installed
+RUN curl -sL https://deb.nodesource.com/setup_8.x | bash -
+
+RUN apt-get update \
+    && apt-get install -y nodejs
+
+RUN curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
+
+RUN echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
+
+RUN apt-get update \
+    && apt-get install -y yarn
+# end stole config
+
 COPY openapi-linter.py .
 COPY openapi.yaml .
 COPY build-docs.sh .