Issue Summary
The setup script fails on rm -rf:

redash-client@6.0.0-beta build /app
npm run clean && NODE_ENV=production node --max-old-space-size=4096 node_modules/.bin/webpack

redash-client@6.0.0-beta clean /app
rm -rf ./client/dist/

/usr/bin/nodejs[117]: …/src/util.h:309:void node::MaybeStackBuffer<T, kStackStorageSize>::AllocateSufficientStorage(size_t) [with T = char; long unsigned int kStackStorageSize = 1024ul; size_t = long unsigned int]: Assertion `(buf_) != (nullptr)’ failed.
1: node::Abort() [node]
2: node::Assert(char const* const (*) [4]) [node]
3: 0x114f6d4 [node]
4: node::crypto::hash::HashUpdate(v8::FunctionCallbackInfov8::Value const&) [node]
5: 0x327d9c75adb8
Aborted (core dumped)

npm ERR! Linux 4.15.0-38-generic
npm ERR! argv “/usr/bin/nodejs” “/usr/bin/npm” “run” “build”
npm ERR! node v6.11.0
npm ERR! npm v3.10.10
npm ERR! code ELIFECYCLE
npm ERR! redash-client@6.0.0-beta build: npm run clean && NODE_ENV=production node --max-old-space-size=4096 node_modules/.bin/webpack
npm ERR! Exit status 134
npm ERR!
npm ERR! Failed at the redash-client@6.0.0-beta build script ‘npm run clean && NODE_ENV=production node --max-old-space-size=4096 node_modules/.bin/webpack’.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the redash-client package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR! npm run clean && NODE_ENV=production node --max-old-space-size=4096 node_modules/.bin/webpack
npm ERR! You can get information on how to open an issue for this project with:
npm ERR! npm bugs redash-client
npm ERR! Or if that isn’t available, you can get their info via:
npm ERR! npm owner ls redash-client
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR! /app/npm-debug.log
ERROR: Service ‘server’ failed to build: The command ‘/bin/sh -c npm install && npm run bundle && npm run build && rm -rf node_modules’ returned a non-zero code: 1

Steps to Reproduce
git clone https://github.com/getredash/redash.git
cd redash/setup && bash setup.sh

Technical details:
Redash Version: Latest
Browser/OS: Ubuntu 18.04 w/ 3 GB RAM and 1 Core
How did you install Redash: Setup Script