Add job to check sync status

.github/workflows/l10n-sync-ru.yml

@@ -0,0 +1,21 @@
+name: l10n-sync-ru
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  sync-status-ru:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Download mdlm
+      run: curl -o- https://raw.githubusercontent.com/markdown-localization/mdlm-sh/v0.0.18/install.sh | bash      
+      
+    - name: Sync status - ru
+      run: |
+        $HOME/.mdlm/mdlm.sh diff ru

README-ru.md

@@ -11,6 +11,7 @@ l10n:p -->
 # Пособие по проектированию систем
 
 <!-- l10n:ignore start -->
+![l10n-sync-ru](https://github.com/voitau/system-design-primer/workflows/l10n-sync-ru/badge.svg)
 > ## Contributing: Russian translation
 >
 > **WARNING**: the document is currently being translated.