npm doesn't install devDependencies content on ci server

I have a private Ember.js project which I am trying to build on CodeShip continuous integration server. To do so I need to install ember-cli which is in my devDependencies. When I do a fresh clone of my project on my machine and npm install I get ember-cli binary in ./node_modules/ember-cli/bin/ember.

However on the CI server, I have only following files:

-rw-rw-r--   1 rof rof  40K Jun  1 15:15 CHANGELOG.md
drwxrwxr-x 105 rof rof 2.1K Jun  2 13:50 node_modules
-rw-rw-r--   1 rof rof 4.1K Mar  6 23:56 package.json
-rw-rw-r--   1 rof rof 6.7K Feb 13 17:22 README.md

Running npm install --verbose I have following lines in log:

npm WARN package.json ember-cli@2.4.2 No bin file found at ./bin/ember
...
npm verb already installed skipping ember-cli@2.4.2 /home/rof/src/http://ift.tt/1sOXmQ9

And similar lines for other devDependencies.

I have checked that NODE_ENV is empty and npm config get production is false. I have also checked that I am using same node (0.12.2) and npm (2.7.4) versions on local machine and CI server.

So my question is: why it works on local machine, but doesn't work on CI server? Is there some configuration value that is missing?