include git output to logs. make checkout of commit if

app/controllers/projects_controller.rb

@@ -55,7 +55,7 @@ class ProjectsController < ApplicationController
     @project = Project.find(params[:id])
     @build = @project.register_build(ref: params[:ref])
-    if @build
+    if @build and @build.id
       Resque.enqueue(Runner, @build.id)
       redirect_to project_build_path(@project, @build)
     else

lib/runner.rb

@@ -23,15 +23,13 @@ class Runner
   def run
     path = project.path
     commands = project.scripts
-
-    return if build.canceled?
+    commands = commands.lines.to_a
+    commands.unshift(prepare_project_cmd(path, build.sha))
     build.run!
-    prepare_project(path, build.ref)
-
     Dir.chdir(path) do
-      commands.each_line do |line|
+      commands.each do |line|
         status = command(line, path)
         build.write_trace(@output)
@@ -92,12 +90,12 @@ class Runner
     @output << @tmp_file.read
   end
-  def prepare_project(path, ref)
+  def prepare_project_cmd(path, ref)
     cmd = []
     cmd << "cd #{path}"
     cmd << "git fetch"
     cmd << "git reset --hard"
-    cmd << "git checkout origin/#{ref}"
-    `#{cmd.join("&&")}`
+    cmd << "git checkout #{ref}"
+    cmd.join(" && ")
   end
 end