Add npm command to change a user's role

This avoids us having to connect directly to the DB to change a user's role.
Now we can simply run "heroku run npm run update_user_role foo@example.com
admin".

package.json

@@ -18,7 +18,8 @@
     "rollback": "knex migrate:rollback",
     "dev": "gulp dev",
     "prestart": "gulp build",
-    "start": "node --optimize_for_size --max_old_space_size=460 --gc_interval=100 server.js"
+    "start": "node --optimize_for_size --max_old_space_size=460 --gc_interval=100 server.js",
+    "update_user_role": "node tools/update_user_role.js"
   },
   "repository": {
     "type": "git",

tools/update_user_role.js

@@ -0,0 +1,38 @@
+/* eslint no-console: 0 */
+
+'use strict';
+
+const User = require('../models/user');
+
+function updateUserRole(email, role) {
+  return User.where({ email })
+    .save({ role }, { patch: true, require: true });
+}
+
+if (require.main === module) {
+  const argv = process.argv;
+  if (argv.length < 3 || argv.length > 4) {
+    console.error(`Usage: node ${__filename} <email> [role]`);
+    process.exit(-1);
+  }
+
+  const email = argv[2];
+  const role = argv[3] || null;
+
+  updateUserRole(email, role)
+    .then(() => {
+      console.log(`Updated user "${email}" to role "${role}"`);
+      process.exit(0);
+    })
+    .catch((err) => {
+      if (err.message === 'No Rows Updated') {
+        console.error(`Could not find an user with email "${email}"`);
+      } else if (err.constraint === 'users_role_check') {
+        console.error(`Role "${role}" is invalid`);
+      } else {
+        console.error(err);
+      }
+
+      process.exit(-1);
+    });
+}