add a npm trends tool

Author: fharper

resources/devrel.md

@@ -14,6 +14,7 @@ Some resources to help Developer Relations do their job
 - [Google Apps Tools](#google-apps-tools)
 - [Learning](#learning)
 - [Mascots](#mascots)
+- [npm Tools](#npm-tools)
 - [Open Source Documentation](#open-source-documentation)
 - [Slack Tools](#slack-tools)
 - [Swag](#swag)
@@ -155,6 +156,10 @@ Never underestimate the power of having a cute company or product related mascot
 
 There is also a non-exhaustive list of some of the most well-known [product mascots in tech](https://en.wikipedia.org/wiki/List_of_computing_mascots).
 
+## npm Tools
+
+- [npm trends](https://npmtrends.com)
+
 ## Open Source Documentation
 
 Here is a non-exhaustive list of closed sources product or company not known for being open which have open source documentation. This could be helpful to show your company the benefits of having the public documentation on GitHub, and that **it's a common practice**.