Docker repository path backward compatibility fix:

- resolve #1765
- create link to old git repository path: `/home/git/gogs-repository`

docker/s6/gogs/setup

@@ -12,7 +12,11 @@ fi
 
 cd /app/gogs
 
+# Link volumed data with app data
 ln -sf /data/gogs/log  ./log
 ln -sf /data/gogs/data ./data
 
+# Backward Compatibility with Docker v0.6.15
+ln -sf /data/git /home/git
+
 chown -R git:git /data /app/gogs ~git/