ci&doc: fix the file path issues and write key comments

Dockerfile

@@ -1,42 +1,48 @@
-# Import Background Image
+# Import Basic Image.
 FROM rust:latest as build
 
-# Set up work path
+# Set up work path.
 WORKDIR /home/app
 
-# Copy the Rust Project Files to Docker Image
+# Copy the Rust Project Files to Docker Image.
+# | Please pay attention to the COPY command, which is defined in Docker docs as follows:
+# | `Note: The directory itself is not copied, just its contents.`
+# | URL: https://docs.docker.com/engine/reference/builder/
 COPY ./Cargo.toml /home/app
-COPY ./src /home/app
+COPY ./src /home/app/src
+COPY ./build.rs /home/app
 
-# Set up Target Environment variable
+# Set up Target Environment variable.
 ENV OUT_DIR /home/app/target
 
-# Cargo build Rust Project
+# Cargo build Rust Project.
 RUN cargo build --release
 
-# Build a production environment Docker Image
+# Build a production environment Docker Image.
 FROM ubuntu:22.04
 LABEL author="Snowball_233"
 
-# Switch to Root account
+# Switch to Root account.
 USER root
 
-# Ubuntu Initialization
+# Ubuntu Initialization.
+# | Please replace the time zone according to your needs.
 RUN \
   ln -snf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime && \
   echo 'Asia/Shanghai' > /etc/timezone && \
   apt-get update && \
   apt-get -y upgrade && \
   apt-get install -y htop vim
 
-# Copy the binary files into Docker Image
-# Please replace the specific path according to your needs
+# Copy the binary files into Docker Image.
+# | Please replace the specific path according to your needs.
 COPY --from=build /home/app/target/release /home/BackendServer
 
-# Clean up build cache
+# Clean up build cache.
 RUN \
   apt-get clean && \
   apt-get autoclean && \
   rm -rf /var/lib/apt/lists/*
 
+# Run bash on start.
 CMD ["bash"]