Split alignItems into separate plugin

defaultConfig.stub.js

@@ -21,6 +21,7 @@ module.exports = {
     display: ['responsive'],
     flexDirection: ['responsive'],
     flexWrap: ['responsive'],
+    alignItems: ['responsive'],
     flexbox: ['responsive'],
     float: ['responsive'],
     fontFamily: ['responsive'],

src/corePlugins.js

@@ -15,6 +15,7 @@ import cursor from './plugins/cursor'
 import display from './plugins/display'
 import flexDirection from './plugins/flexDirection'
 import flexWrap from './plugins/flexWrap'
+import alignItems from './plugins/alignItems'
 import flexbox from './plugins/flexbox'
 import float from './plugins/float'
 import fontFamily from './plugins/fontFamily'
@@ -91,6 +92,7 @@ export default function(config) {
     display,
     flexDirection,
     flexWrap,
+    alignItems,
     flexbox,
     float,
     fontFamily,

src/plugins/alignItems.js

@@ -0,0 +1,24 @@
+export default function({ variants }) {
+  return function({ addUtilities }) {
+    addUtilities(
+      {
+        '.items-start': {
+          'align-items': 'flex-start',
+        },
+        '.items-end': {
+          'align-items': 'flex-end',
+        },
+        '.items-center': {
+          'align-items': 'center',
+        },
+        '.items-baseline': {
+          'align-items': 'baseline',
+        },
+        '.items-stretch': {
+          'align-items': 'stretch',
+        },
+      },
+      variants
+    )
+  }
+}

src/plugins/flexbox.js

@@ -2,21 +2,6 @@ export default function({ variants }) {
   return function({ addUtilities }) {
     addUtilities(
       {
-        '.items-start': {
-          'align-items': 'flex-start',
-        },
-        '.items-end': {
-          'align-items': 'flex-end',
-        },
-        '.items-center': {
-          'align-items': 'center',
-        },
-        '.items-baseline': {
-          'align-items': 'baseline',
-        },
-        '.items-stretch': {
-          'align-items': 'stretch',
-        },
         '.self-auto': {
           'align-self': 'auto',
         },