Update translation files

po/HACKING.md

@@ -0,0 +1,27 @@
+# Internationalization
+
+Execute the following commands from the project root directory to update
+translation files whenever translatable strings have been changed.
+
+## 1. Update `template.pot`
+
+```bash
+xgettext \
+    --from-code=UTF-8 \
+    --add-comments \
+    --keyword=_ \
+    --keyword=C_:1c,2 \
+    --files-from=po/POTFILES \
+    --output=po/template.pot
+```
+
+## 2. Update translation files
+
+```bash
+msgmerge \
+    --update \
+    --backup=off \
+    --no-fuzzy-matching \
+    po/de.po \
+    po/template.pot
+```