Add jenkins.sh for builds

jenkins.sh

@@ -0,0 +1,9 @@
+#!/bin/bash -l
+export NVM_DIR="/home/jenkins/.nvm"
+[ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh"
+nvm use 4
+npm install
+(cd node_modules/matrix-react-sdk && npm run build) # npm doesn't do this when dependencies point at github.com >:(
+npm run build # Dumps artificats to /vector
+rm vector-build.tar.gz || true # rm previous artifacts without failing if it doesn't exist
+tar -zcvhf vector-build.tar.gz vector #g[z]ip, [c]reate archive, [v]erbose, [f]ilename, [h]ard-dereference (do not archive symlinks)