docs: add Docker usage guide and update WP-CLI setup in Dockerfile

Author: tanhongit

php84/Dockerfile

@@ -45,12 +45,19 @@ RUN mkdir -p /home/csdev/.wp-cli/cache && \
     chown -R csdev:csdev /home/csdev/.wp-cli && \
     chmod 777 /home/csdev/.wp-cli/cache
 
-# Add WP-CLI bash completion
-RUN curl -o /etc/bash_completion.d/wp-completion.bash https://raw.githubusercontent.com/wp-cli/wp-cli/main/utils/wp-completion.bash
+# Create necessary directories for WP-CLI
+RUN mkdir -p /home/csdev/.wp-cli/cache && \
+    chown -R csdev:csdev /home/csdev/.wp-cli && \
+    chmod 777 /home/csdev/.wp-cli/cache
 
+# Switch to non-root user
 USER csdev
 
 # Set WP-CLI configuration
 ENV WP_CLI_CACHE_DIR=/home/csdev/.wp-cli/cache
 
+# Install bash completion for WP-CLI (optional, can be done later if needed)
+# RUN curl -s https://raw.githubusercontent.com/wp-cli/wp-cli/main/utils/wp-completion.bash > ~/.wp-completion.bash \
+#     && echo "source ~/.wp-completion.bash" >> ~/.bashrc
+
 CMD ["php-fpm"]