Unhandled rejection Error: Exit code: ENOENT. spawn gm ENOENT

[blahah]

I know the general solution to this has been addressed multiple times, but I wanted to share the specific solution that worked for me in case it affects anyone else.

Trying to build on Linux with Travis, I got this error:

Packaging for linux x64 using electron 1.6.4 to dist/linux-unpacked
Unhandled rejection Error: Exit code: ENOENT. spawn gm ENOENT
    at /home/travis/build/codeforscience/sciencefair/node_modules/electron-builder-util/src/util.ts:75:16
    at exithandler (child_process.js:212:5)
    at ChildProcess.errorhandler (child_process.js:224:5)
    at emitOne (events.js:96:13)
    at ChildProcess.emit (events.js:191:7)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:213:12)
    at onErrorNT (internal/child_process.js:367:16)
    at _combinedTickCallback (internal/process/next_tick.js:80:11)
    at process._tickCallback (internal/process/next_tick.js:104:9)

The linux instructions in the wiki explain that some packages must be installed, including graphicsmagick, which is where the gm binary should come from.

When I added the apt-get lines from the wiki to my .travis.yml install script, it didn't work. There was no error that I could see during install, but the gm binary was not available.

The fix was to use the .travis.yml syntax for specifying apt packages to install. Having this key at the top level of the .travis.yml file solved the problem:

addons:
  apt:
    packages:
      - libgnome-keyring-dev
      - icnsutils
      - graphicsmagick
      - xz-utils
      - rpm
      - bsdtar

I'm closing this issue immediately - I just wanted it available to anyone searching.