Move branch creation logic in service

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/controllers/projects/branches_controller.rb

@@ -16,11 +16,7 @@ def recent
   end
 
   def create
-    @repository.add_branch(params[:branch_name], params[:ref])
-
-    if new_branch = @repository.find_branch(params[:branch_name])
-      Event.create_ref_event(@project, current_user, new_branch, 'add')
-    end
+    CreateBranchService.new.execute(project, params[:branch_name], params[:ref], current_user)
 
     redirect_to project_branches_path(@project)
   end

app/services/create_branch_service.rb

+class CreateBranchService
+  def execute(project, branch_name, ref, current_user)
+    repository = project.repository
+    repository.add_branch(branch_name, ref)
+    new_branch = repository.find_branch(branch_name)
+
+    if new_branch
+      Event.create_ref_event(project, current_user, new_branch, 'add')
+    end
+
+    new_branch
+  end
+end