Add babel-core README

packages/babel-core/README.md

@@ -1 +1,24 @@
 # babel-core
+
+> Babel compiler core.
+
+## Install
+
+```
+$ npm install babel-core
+```
+
+## Usage
+
+```js
+import babel from 'babel-core';
+
+const code = `class Example {}`;
+const result = babel.transform(code, { /* options */ });
+
+result.code; // Generated code
+result.map; // Sourcemap
+result.ast; // AST
+```
+
+For more in depth documentation see: http://babeljs.io/docs/usage/api/