cache client/node_modules during heroku deploys

[modosc]

without this heroku has to do a full npm install on every deploy - i guess this could be part of the heroku generators but it seemed like a lot more work to modify this file there than to just add this option here.

---

This change is

[justin808]

@modosc This looks great. Can you please add a couple sentences to the heroku doc page.

Also, maybe this is more generic than heroku?

[justin808]

Additionally, we have to see why the CI build does not pass with this.

[modosc]

seems like it failed for an unrelated reason:

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty-updates/main/source/Sources  Hash Sum mismatch
W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty-updates/main/binary-amd64/Packages  Hash Sum mismatch
W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty-updates/universe/binary-amd64/Packages  Hash Sum mismatch
E: Some index files failed to download. They have been ignored, or old ones used instead.

i can't seem to retrigger the build tho.

[justin808]

@modosc any word on this one?

[modosc]

updated docs, let's see if ci is happy today.

[justin808]

@modosc Please rebase on top of master to a single commit. Thanks.

[coveralls]

Coverage remained the same at 87.515% when pulling 7e78ae4 on modosc:patch-1 into e6fa8c4 on shakacode:master.

[justin808]

@modosc there should be no node_modules directory, right? Just client/node_modules.

[modosc]

it's possible the app has one for some other reason (separate service, browserify integration, etc) and it's the heroku default if nothing else set so i figured it made sense to keep it just in case.

[justin808]

OK

[coveralls]

Coverage remained the same at 87.396% when pulling 284f0d2 on modosc:patch-1 into da9d525 on shakacode:master.

[justin808]

@modosc can you please rebase on top of master. I want to merge this.

[justin808]

@modosc I'm ready to merge your changes. However, we need to rebase on top of master, after squashing to one commit, and please include the changelog entry.

[justin808]

@modosc Ping, Ping. I'm ready to merge your changes. However, we need to rebase on top of master, after squashing to one commit, and please include the changelog entry.

[modosc]

@justin808 should be done?

[coveralls]

Coverage remained the same at 82.473% when pulling d1925a6 on modosc:patch-1 into 9491179 on shakacode:master.

[justin808]

Manually merged in #415.