add hot key:Navigate up(Ctrl + P) for CodeEditor

lib/components/CodeEditor.js

@@ -31,6 +31,14 @@ module.exports = React.createClass({
     editor.setTheme('ace/theme/xcode')
     editor.clearSelection()
     editor.moveCursorTo(0, 0)
+    editor.commands.addCommand({
+      name: 'Emacs cursor up',
+      bindKey: {mac: 'Ctrl-P'},
+      exec: function (editor) {
+        editor.navigateUp(1)
+      },
+      readOnly: true
+    })
 
     editor.setReadOnly(!!this.props.readOnly)