Add chroma color library. (#665)

* Add chroma color library.

* oops comma

* Last comma?

packages.json

@@ -8493,6 +8493,19 @@
     "description": "i3 IPC client library",
     "license": "LGPLv3",
     "web": "https://github.com/FedericoCeratto/nim-i3ipc"
-  }
+  },
-
+  {
+    "name": "chroma",
+    "url": "https://github.com/treeform/chroma",
+    "method": "git",
+    "tags": [
+      "colors",
+      "cmyk",
+      "hsl",
+      "hsv"
+    ],
+    "description": "Everything you want to do with colors.",
+    "license": "MIT",
+    "web": "https://github.com/treeform/chroma"
+  } 
 ]