Add PostCSS text color utilities

src/generators/textColors.js

@@ -0,0 +1,11 @@
+import _ from 'lodash'
+import defineClass from '../util/defineClass'
+import normalizeColorList from '../util/normalizeColorList'
+
+export default function ({ colors, text }) {
+  return _.map(normalizeColorList(text.colors, colors), (color, modifier) => {
+    return defineClass(`text-${modifier}`, {
+      'color': color,
+    })
+  })
+}