Add username field to push webhook

Signed-off-by: David Turner <novalis@novalis.org>

changelogs/unreleased/dturner-username.yml

+---
+title: add username field to push webhook
+merge_request:
+author: David Turner

doc/user/project/integrations/webhooks.md

@@ -74,6 +74,7 @@ X-Gitlab-Event: Push Hook
   "checkout_sha": "da1560886d4f094c3e6c9ef40349f7d38b5d27d7",
   "user_id": 4,
   "user_name": "John Smith",
+  "user_username": "jsmith",
   "user_email": "john@example.com",
   "user_avatar": "https://s.gravatar.com/avatar/d4c74594d841139328695756648b6bd6?s=8://s.gravatar.com/avatar/d4c74594d841139328695756648b6bd6?s=80",
   "project_id": 15,

lib/gitlab/data_builder/push.rb

@@ -11,6 +11,7 @@ module Gitlab
       #   ref: String,
       #   user_id: String,
       #   user_name: String,
+      #   user_username: String,
       #   user_email: String
       #   project_id: String,
       #   repository: {
@@ -51,6 +52,7 @@ module Gitlab
           message: message,
           user_id: user.id,
           user_name: user.name,
+          user_username: user.username,
           user_email: user.email,
           user_avatar: user.avatar_url,
           project_id: project.id,

spec/lib/gitlab/data_builder/push_spec.rb

@@ -35,6 +35,7 @@ describe Gitlab::DataBuilder::Push, lib: true do
     it { expect(data[:ref]).to eq('refs/tags/v1.1.0') }
     it { expect(data[:user_id]).to eq(user.id) }
     it { expect(data[:user_name]).to eq(user.name) }
+    it { expect(data[:user_username]).to eq(user.username) }
     it { expect(data[:user_email]).to eq(user.email) }
     it { expect(data[:user_avatar]).to eq(user.avatar_url) }
     it { expect(data[:project_id]).to eq(project.id) }