Common errors on update from upstream

Error:
Completed 500 Internal Server Error in 315ms (ActiveRecord: 53.8ms)

NoMethodError (undefined method enable_experiments' for #<Group:0x00000005f0a960>
Did you mean? enable_warnings):
app/models/event_collection.rb:13:inserialize!'
config/initializers/event_bus.rb:66:in block (2 levels) in <top (required)>'
app/extras/event_bus.rb:8:inblock in broadcast'
app/extras/event_bus.rb:8:in broadcast'
app/models/events/new_comment.rb:7:inblock in publish!'
app/models/events/new_comment.rb:7:in tap'
app/models/events/new_comment.rb:7:inpublish!'
app/extras/example_content.rb:6:in block in add_to_group!'
app/extras/example_content.rb:5:intap'
app/extras/example_content.rb:5:in add_to_group!'
app/services/group_service.rb:9:increate'
app/controllers/api/restful_controller.rb:12:in create_action'
app/controllers/api/groups_controller.rb:17:increate'

Solution:
rake db:migrate

Error:

loomio/angular$ gulp dev
[17:44:03] Failed to load external module coffee-script/register
[17:44:03] Failed to load external module coffee-script

/home/gaspar/projects/loomio-test3/loomio/angular/gulpfile.coffee:1
(exports, require, module, __filename, __dirname) { gulp = require 'gulp'
^{^}
SyntaxError: Unexpected string
at Module._compile (module.js:439:25)
at Object.Module._extensions..js (module.js:474:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Module.require (module.js:364:17)
at require (module.js:380:17)
at Liftoff.handleArguments (/usr/local/lib/node_modules/gulp/bin/gulp.js:116:3)
at Liftoff. (/usr/local/lib/node_modules/gulp/node_modules/liftoff/index.js:193:16)
at module.exports (/usr/local/lib/node_modules/gulp/node_modules/liftoff/node_modules/flagged-respawn/index.js:17:3)
at Liftoff. (/usr/local/lib/node_modules/gulp/node_modules/liftoff/index.js:185:9)

Solution:
sudo gem install bundler
sudo gem install rake
bundle install
sudo npm install -g bower
sudo npm install -g gulp
sudo npm install -g gulp-sass --save-dev

cd angular
sudo npm install gulp
sudo npm update
sudo npm install

Thanks for the hints, I've got the same error and gulp dev stalls at Finished 'compile-fast' after 54 μs. I tried this:

$ cd loomio
$ sudo gem install bundler 
$ sudo gem install rake bundle
$ sudo npm install -g bower 
$ sudo npm install -g gulp 
$ sudo npm install -g gulp-sass --save-dev
$ cd angular 
$ sudo npm install gulp 
$ sudo npm update && sudo npm install```

Note that after `sudo npm install -g bower` i get a warning:

npm WARN deprecated bower@1.8.2: ...psst! Your project can stop working at any moment because its dependencies can change. Prevent this by migrating to Yarn: https://bower.io/blog/2017/how-to-migrate-away-from-bower/
/usr/local/bin/bower -> /usr/local/lib/node_modules/bower/bin/bower
/usr/local/lib
└── bower@1.8.2

and after `$ sudo npm install -g gulp-sass --save-dev`

loadDep:uuid → resolveWit ▄ ╢███████████████░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░╟
WARN engine hawk@6.0.2: wanted: {"node":">=4.5.0"} (current: {"node":"4.2.6","np

node-sass@4.6.1 install /usr/local/lib/node_modules/gulp-sass/node_modules/node-sass
node scripts/install.js

sh: 1: node: not found
/usr/local/lib
└── (empty)

npm ERR! Linux 4.4.0-98-generic
npm ERR! argv "/usr/bin/nodejs" "/usr/bin/npm" "install" "-g" "gulp-sass" "--save-dev"
npm ERR! node v4.2.6
npm ERR! npm v3.5.2
npm ERR! file sh
npm ERR! code ELIFECYCLE
npm ERR! errno ENOENT
npm ERR! syscall spawn

npm ERR! node-sass@4.6.1 install: node scripts/install.js
npm ERR! spawn ENOENT
npm ERR!
npm ERR! Failed at the node-sass@4.6.1 install script 'node scripts/install.js'.
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 node-sass package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR! node scripts/install.js
npm ERR! You can get information on how to open an issue for this project with:
npm ERR! npm bugs node-sass
npm ERR! Or if that isn't available, you can get their info via:
npm ERR! npm owner ls node-sass
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR! loomio/npm-debug.log
npm ERR! code 1
```
@robertguthrie Are these commands "officially" recommended? If so, I'd be happy to add them in the doc.

Any hint on how to fix my gulp dev error (I'm running Linux Mint 18.2)?

I don't think you need bower at all, and the only globally installed npm modules needed are yarn and gulp

bundle install
npm install -g yarn gulp
cd angular
yarn

Although npm rebuild node-sass has been known to be very useful. And if you ever get into problems, then rm -rf node_modules && yarn again