added snippet config in setting

browser/main/modals/PreferencesModal/SnippetEditor.js

@@ -0,0 +1,66 @@
+import CodeMirror from 'codemirror'
+import PropTypes from 'prop-types'
+import React from 'react'
+import _ from 'lodash'
+
+const defaultEditorFontFamily = ['Monaco', 'Menlo', 'Ubuntu Mono', 'Consolas', 'source-code-pro', 'monospace']
+const buildCMRulers = (rulers, enableRulers) =>
+  enableRulers ? rulers.map(ruler => ({ column: ruler })) : []
+
+export default class SnippetEditor extends React.Component {
+  constructor (props) {
+    super(props)
+  }
+
+  componentDidMount () {
+    const { rulers, enableRulers } = this.props
+    let cm = CodeMirror(this.refs.root, {
+      rulers: buildCMRulers(rulers, enableRulers),
+      lineNumbers: this.props.displayLineNumbers,
+      lineWrapping: true,
+      theme: this.props.theme,
+      indentUnit: this.props.indentSize,
+      tabSize: this.props.indentSize,
+      indentWithTabs: this.props.indentType !== 'space',
+      keyMap: this.props.keyMap,
+      scrollPastEnd: this.props.scrollPastEnd,
+      dragDrop: false,
+      foldGutter: true,
+      gutters: ['CodeMirror-linenumbers', 'CodeMirror-foldgutter'],
+      autoCloseBrackets: true,
+    })
+    cm.setValue("asdasd")
+    cm.setSize("100%", "100%")
+  }
+
+  render() {
+    const { fontSize } = this.props
+    let fontFamily = this.props.fontFamily
+    fontFamily = _.isString(fontFamily) && fontFamily.length > 0
+      ? [fontFamily].concat(defaultEditorFontFamily)
+      : defaultEditorFontFamily
+    return (
+      <div 
+      styleName="SnippetEditor"
+      ref='root'
+      tabIndex='-1'
+      style={{
+        fontFamily: defaultEditorFontFamily.join(', '),
+        fontSize: fontSize,
+        position: 'relative',
+        height: 'calc(100vh - 310px)'
+      }}>
+      </div>
+    )
+  }
+}
+
+SnippetEditor.defaultProps = {
+  readOnly: false,
+  theme: 'xcode',
+  keyMap: 'sublime',
+  fontSize: 14,
+  fontFamily: 'Monaco, Consolas',
+  indentSize: 4,
+  indentType: 'space'
+}