fix(docs): update Heroku deployment instructions

[JustinTRoss]

Description

• Added CLI instructions for adding Heroku buildpacks
• Removed misleading instructions.

[DSchau]

Looks good. Could you explain why the section you removed is misleading and why it's not needed?

Would just help me understand; thanks!

[JustinTRoss]

Certainly. The section I removed was misleading for a couple reasons.

1. Heroku doesn't run npm start if you're using heroku-buildpack-static. It's only if you're using heroku/node without heroku-buildpack-static.
2. Serving from gatsby serve is an unoptimized alternative to heroku-buildpack-static, which itself creates a file server.

[JustinTRoss]

@DSchau Let me know if you have any questions.

[DSchau]

Thanks for this!

[gatsbot]

Holy buckets, @JustinTRoss — we just merged your PR to Gatsby! 💪💜

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Thanks again!

[aleccaputo]

hey guys quick question, i'm having trouble deploying to heroku, logs are dumping this out:

2019-02-11T03:38:51.734304+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/"

The app builds, but errors out when i try to access the domain. Any ideas why this is happening? I followed the heroku docs @JustinTRoss

[JustinTRoss]

@aleccaputo I have only seen that when trying to serve with gatsby serve and/or trying to bind ports. Take a look at the log and make sure it's serving properly with heroku-buildpack-static.

[aleccaputo]

@JustinTRoss here's my build log

-----> Static HTML app detected
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
-----> Installed directory to /app/bin
-----> Node.js app detected
       
-----> Creating runtime environment
       
       NPM_CONFIG_LOGLEVEL=error
       NODE_ENV=production
       NODE_MODULES_CACHE=true
       NODE_VERBOSE=false
       
-----> Installing binaries
       engines.node (package.json):  10.3.0
       engines.npm (package.json):   unspecified (use default)
       
       Resolving node version 10.3.0...
       Downloading and installing node 10.3.0...
       Using default npm version: 6.1.0
       
-----> Restoring cache
       - node_modules
       
-----> Building dependencies
       Installing node modules (package.json + package-lock)
       audited 25033 packages in 18.024s
       found 0 vulnerabilities
       
       Running heroku-postbuild
       
       > [email protected] heroku-postbuild /tmp/build_c4280b0f3235bcb2c9c2846e2429c77d
       > gatsby build
       
lscpu: failed to determine number of CPUs: /sys/devices/system/cpu/possible: No such file or directory
       success open and validate gatsby-configs — 0.133 s
       success load plugins — 0.305 s
       success onPreInit — 0.551 s
       success delete html and css files from previous builds — 0.007 s
       success initialize cache — 0.010 s
       success copy gatsby files — 0.032 s
       success onPreBootstrap — 0.006 s
       success source and transform nodes — 0.069 s
       success building schema — 0.423 s
       success createPages — 0.001 s
       success createPagesStatefully — 0.038 s
       success onPreExtractQueries — 0.005 s
       success update schema — 0.262 s
       success extract queries from components — 0.206 s
       success run graphql queries — 0.205 s — 4/4 19.58 queries/second
       success write out page data — 0.005 s
       success write out redirect data — 0.001 s
       
       
       info bootstrap finished - 4.738 s
       
       done generating icons for manifest
       success onPostBootstrap — 0.261 s
       success Building production JavaScript and CSS bundles — 8.960 s
       {"socialMediaLinks":{"linkedIn":"zzz","github":"xxx","email":"yyy"}}
       success Building static HTML for pages — 1.513 s — 1/1 3.94 pages/second
       info Done building in 15.476 sec
       
-----> Caching build
       - node_modules
       
-----> Pruning devDependencies
       audited 25033 packages in 16.56s
       found 0 vulnerabilities
       
       
-----> Build succeeded!
-----> Discovering process types
       Procfile declares types     -> (none)
       Default types for buildpack -> web
-----> Compressing...
       Done: 77.2M
-----> Launching...
       Released v8

[aleccaputo]

oh hey, i figured it out! Turns out somehow when i copy and pasted https://github.com/heroku/heroku-buildpack-static as a buildpack on heroku, it added .git to the end of the url. When i removed that, it fixed my issue. Not sure how that happened, I certainly didn't type it. I might have selected it from a suggestion it gave me