Fix permissions

Author: rigon

Dockerfile

@@ -16,6 +16,6 @@ RUN ln -svf ../../README.md files/readme/readme.md && \
     ln -svf ../../EXAMPLES.md files/examples/examples.md && \
     ln -svf ../../MARKDOWN-STYLES.md files/markdown_styles/markdown_styles.md && \
     chmod a-w README.md EXAMPLES.md MARKDOWN-STYLES.md && \
-    chown www-data files/ && \
+    chown -Rv www-data:www-data files/ && \
     echo "upload_max_filesize = 50M" > /usr/local/etc/php/conf.d/upload_size.ini && \
     echo "post_max_size = 50M" >> /usr/local/etc/php/conf.d/upload_size.ini