doc: add docs for cgroup

docs/zh_CN/workers.conf

@@ -5,7 +5,7 @@ name = "mirror_worker"
 log_dir = "/srv/tunasync/log/tunasync/{{.Name}}"
 mirror_dir = "/srv/tunasync"
 concurrent = 10
-interval = 1
+interval = 120
 
 # ensure the exec user be add into `docker` group
 [docker]
@@ -176,7 +176,7 @@ command = "/home/scripts/pub.sh"
 interval = 30
 docker_image = "tunathu/pub-mirror:latest"
 
-        [mirrors.env] 
+        [mirrors.env]
         MIRROR_BASE_URL = "https://mirrors.tuna.tsinghua.edu.cn/dart-pub"
 
 [[mirrors]]
@@ -604,7 +604,7 @@ docker_volumes = [
 ]
 docker_options = [
 ]
-        [mirrors.env] 
+        [mirrors.env]
         MIRROR_BASE_URL = "https://mirrors.tuna.tsinghua.edu.cn/rustup"
 
 [[mirrors]]
@@ -710,7 +710,7 @@ command = "/home/tunasync-scripts/aosp.sh"
 upstream = "https://android.googlesource.com/mirror/manifest"
 size_pattern = "Total size is ([0-9\\.]+[KMGTP]?)"
 docker_image = "tunathu/tunasync-scripts:latest"
-        [mirrors.env] 
+        [mirrors.env]
         REPO = "/usr/local/bin/aosp-repo"
         REPO_URL = "https://mirrors.tuna.tsinghua.edu.cn/git/git-repo"
         USE_BITMAP_INDEX = "1"
@@ -737,7 +737,7 @@ upstream = "https://chromium.googlesource.com"
 size_pattern = "Total size is ([0-9\\.]+[KMGTP]?)"
 fail_on_match = "fatal: "
 docker_image = "tunathu/tunasync-scripts:latest"
-        [mirrors.env] 
+        [mirrors.env]
         USE_BITMAP_INDEX = "1"
         CONCURRENT_JOBS = "20"