Rust bindings: Make it able to publish this crate

I added
- data required to publish this crate to `crates.io`.
- README.md which contains the details of how to publish this crate.

rust/Cargo.toml.in

@@ -17,7 +17,10 @@
 
 [package]
 name = "guestfs"
-version = "@VERSION@"
+version = "0.1.0-compat@VERSION@"
 edition = "2018"
+authors = ["Hiroyuki Katsura <hiroyuki.katsura.0513@gmail.com>"]
+description = "libguestfs bindings for Rust"
+license-file = "../COPYING"
 
 [dependencies]

rust/README.md

@@ -0,0 +1,42 @@
+# libguestfs bindings for Rust
+
+This package contains the libguestfs bindings for Rust. You can use this crate
+by using cargo. See [crates.io](https://https://crates.io/crates/guestfs)
+
+# For maintainer
+
+## How to test
+
+Tests are incorporated into the build system.
+
+You can test it manually by
+
+```
+$ ../run cargo test
+```
+
+## How to publish
+
+### 1. Fix version in Cargo.toml.in
+
+Regarding Versioning convention, see [Semantic
+Versioning](https://semver.org/).
+
+You must not break '-compat@VERSION@' to make sure that this binding is
+compatible with the installed libguestfs.
+
+Example
+```
+version = "0.1.0-compat@VERSION@"
+```
+
+### 2. Commit the change of the version
+
+### 3. Build libguestfs
+
+### 4. Publish
+
+```
+$ cargo publish
+```
+