Merge pull request #2564 from thegrowthmill/master

docs(who-uses): add growthmill

Author: kamilmysliwiec

content/discover/who-uses.json

@@ -270,6 +270,7 @@
     "https://swetrix.com",
     "https://swyftlogistics.com",
     "https://evershop.io",
-    "https://e-design.ca"
+    "https://e-design.ca",
+    "https://growthmill.com"
   ]
 }