Add the README.md.

Author: lsk569937453

README.md

@@ -0,0 +1,20 @@
+# READ ME
+## How to use
+```
+kt -t 100 -s 5 http://httpbin.org
+```
+The above command means use 100 threads to request the httpbin.org for 5 second.
+
+## The options
+```
+Usage: kt.exe [OPTIONS] <URL>
+
+Arguments:
+  <URL>  The request url,like http://www.google.com
+
+Options:
+  -t, --threads <Threads count>              The thread count [default: 20]
+  -s, --sleep-seconds <The running seconds>  The thread count [default: 3]
+  -h, --help                                 Print help
+  -V, --version                              Print version
+```

src/main.rs

@@ -29,7 +29,7 @@ struct Cli {
     /// The thread count.
     #[arg(short = 't', long, value_name = "Threads count", default_value_t = 20)]
     threads: u16,
-    /// The thread count.
+    /// The running seconds for the testing tools.
     #[arg(
         short = 's',
         long,