feat(worker): Implemented docker executor, close #55

if docker is enabled in configure file and `docker_image` is set on mirror config, the command would

be executed via `docker run ...`

worker/config.go

@@ -38,6 +38,7 @@ type Config struct {
 	Server  serverConfig   `toml:"server"`
 	Cgroup  cgroupConfig   `toml:"cgroup"`
 	ZFS     zfsConfig      `toml:"zfs"`
+	Docker  dockerConfig   `toml:"docker"`
 	Include includeConfig  `toml:"include"`
 	Mirrors []mirrorConfig `toml:"mirrors"`
 }
@@ -74,6 +75,12 @@ type cgroupConfig struct {
 	Group    string `toml:"group"`
 }
 
+type dockerConfig struct {
+	Enable  bool     `toml:"enable"`
+	Volumes []string `toml:"volumes"`
+	Options []string `toml:"options"`
+}
+
 type zfsConfig struct {
 	Enable bool   `toml:"enable"`
 	Zpool  string `toml:"zpool"`
@@ -111,6 +118,10 @@ type mirrorConfig struct {
 	Username      string `toml:"username"`
 	Password      string `toml:"password"`
 	Stage1Profile string `toml:"stage1_profile"`
+
+	DockerImage   string   `toml:"docker_image"`
+	DockerVolumes []string `toml:"docker_volumes"`
+	DockerOptions []string `toml:"docker_options"`
 }
 
 // LoadConfig loads configuration