docs(readme): perfect document.

README.md

@@ -9,10 +9,36 @@ Standardized Git submission tool. “Grc” is a temporary name.
 
 Similar to git-cz, gcr will help you to provide a better Git experience.
 
-## Using
+## Install
+
+You can install **grc** in the following ways:
+
+### From Cargo
+
+Please Run `cargo install grc`.
+
+### Release Package
 
-after the tools install, run command:
+Go to [RELEASE](https://github.com/sdttttt/gcr/releases), download one you like.
+
+### From Source
+
+Please Run:
 
 ```bash
-grc
+git clone --depth=1 https://github.com/sdttttt/gcr.git
+
+cd gcr
+
+cargo build --release
+```
+
+grc under `target/release/`.
+
+## Using
+
+after the tools install, run command in your repository:
+
 ```
+grc
+```

src/arguments.rs

@@ -12,6 +12,7 @@ enum Mode {
     Commit,
 }
 
+
 pub struct Arguments {
     mode: Mode
 }