Fix CreateBranchService after Repository#commit_file was renamed to create_file

Closes #29687

app/services/create_branch_service.rb

@@ -25,12 +25,12 @@ class CreateBranchService < BaseService
   private
 
   def create_master_branch
-    project.repository.commit_file(
+    project.repository.create_file(
       current_user,
       '/README.md',
       '',
       message: 'Add README.md',
-      branch_name: 'master',
-      update: false)
+      branch_name: 'master'
+    )
   end
 end

spec/services/create_branch_service_spec.rb

@@ -0,0 +1,24 @@
+require 'spec_helper'
+
+describe CreateBranchService, services: true do
+  let(:user) { create(:user) }
+  let(:service) { described_class.new(project, user) }
+
+  describe '#execute' do
+    context 'when repository is empty' do
+      let(:project) { create(:project_empty_repo) }
+
+      it 'creates master branch' do
+        service.execute('my-feature', 'master')
+
+        expect(project.repository.branch_exists?('master')).to be_truthy
+      end
+
+      it 'creates my-feature branch' do
+        service.execute('my-feature', 'master')
+
+        expect(project.repository.branch_exists?('my-feature')).to be_truthy
+      end
+    end
+  end
+end