Add release wizard

tools/tag-release.js

@@ -0,0 +1,18 @@
+const { exec } = require('child_process')
+
+module.exports = () => {
+  return new Promise((resolve, reject) => {
+    const version = require('../package.json').version
+    exec(`git tag v${version}`, err => {
+      if (err) {
+        console.error(`There was a problem creating the new tag. Typically, this happens when it already exists, in which case you can delete it with
+git tag -d <name of tag>
+or you might not have made the file executable yet, which you can do by running
+chmod +x ./tools/tag-release`)
+        reject(err.message)
+      } else {
+        resolve()
+      }
+    })
+  })
+}