added delete snippet, update snippet, create snippet and save on snippet change

browser/main/lib/dataApi/deleteSnippet.js

@@ -0,0 +1,20 @@
+const { remote } = require('electron')
+import fs from 'fs'
+import path from 'path'
+import consts from 'browser/lib/consts'
+
+function deleteSnippet (snippets, snippetId) {
+  return new Promise((resolve, reject) => {
+    for(let i = 0; i < snippets.length; i++) {
+      if (snippets[i].id === snippetId) {
+        snippets.splice(i, 1);
+        fs.writeFile(consts.SNIPPET_FILE, JSON.stringify(snippets, null, 4), (err) => {
+          if (err) reject(err)
+          resolve(snippets)
+        })
+      }
+    }
+  }) 
+}
+
+module.exports = deleteSnippet