Added The Docker Command to install configurable-http-proxy (#1633)

* Added The Docker Command to install configurable-http-proxy

Author: MATRIX4284

doc/k8s/sqlflowhub/Dockerfile

@@ -1,8 +1,14 @@
 FROM sqlflow/sqlflow
 
+# Installed npm
+RUN apt-get -y install npm
+
 RUN mkdir -p /etc/jhub && \
     bash -c "pip install jupyterhub && \
     pip install notebook"
+    
+# Added to get rid of the of the Proxy Config Folder not founf Errror resulting in POD crash    
+RUN npm install -g configurable-http-proxy
 
 COPY jupyterhub_config.py /etc/jhub/jupyterhub_config.py