Remove postinstall (#532)

CONTRIBUTING.md

@@ -51,6 +51,9 @@ them with auto-reload.
 
 ## Docs
 
+The documentation lives in the `./docs` folder. You should start by installing
+its dependencies with `cd ./docs && yarn install`. Then:
+
 - `yarn docs:build` will build the docs website in `./docs/dist`.
 - `yarn docs:serve` will do the same, but with live-reload enabled
 - `yarn docs:deploy` will deploy the doc website manually

package.json

@@ -17,8 +17,7 @@
     "release": "./scripts/release",
     "serve": "./scripts/serve",
     "test": "./scripts/test",
-    "test:watch": "./scripts/test-watch",
-    "postinstall": "cd ./docs && yarn install"
+    "test:watch": "./scripts/test-watch"
   },
   "files": [
     "dist/"