Fix opencollective postinstall in package.json for production builds (#173)

* Fix opencollective postinstall in package.json for production builds

* Fix link to contributors in README

Author: philquinn

README.md

@@ -728,7 +728,7 @@ A function that resets the form values to their last initialized values.
 ## Contributors
 
 This project exists thanks to all the people who contribute. [[Contribute](CONTRIBUTING.md)].
-<a href="graphs/contributors"><img src="https://opencollective.com/final-form/contributors.svg?width=890" /></a>
+<a href="https://github.com/final-form/react-final-form/graphs/contributors"><img src="https://opencollective.com/final-form/contributors.svg?width=890" /></a>
 
 ## Backers
 

package.json

@@ -12,7 +12,7 @@
     "start": "nps",
     "test": "nps test",
     "precommit": "lint-staged && npm start validate",
-    "postinstall": "opencollective postinstall"
+    "postinstall": "opencollective postinstall || exit 0"
   },
   "author":
     "Erik Rasmussen <[email protected]> (http://github.com/erikras)",