add readme

Author: tyan-boot

README.MD

@@ -0,0 +1,36 @@
+# fido-rs
+
+libfido2 bindings for the Rust programming language.
+
+# Example
+
+1. Make a credential
+```rust
+use fido2_rs::device::Device;
+use fido2_rs::credentials::CredentialRequest;
+use fido2_rs::credentials::CoseType;
+use anyhow::Result;
+
+fn main() -> Result<()> {
+    let dev = Device::open("windows://hello").expect("unable open windows hello");
+ 
+    let request = CredentialRequest::builder()
+        .client_data(&[1, 2, 3, 4, 5, 6])?
+        .rp("fido_rs", "fido example")?
+        .user(&[1, 2, 3, 4, 5, 6], "alice", Some("alice"), None)?
+        .cose_type(CoseType::RS256)?
+        .build();
+    let cred = dev.make_credential(request, None)?;
+    dbg!(cred.id());
+    Ok(())
+}
+```
+
+# Support platform
+* Windows (MSVC and MinGW)
+* Linux
+
+# TODO
+
+* [ ] more doc
+* [ ] full bindings to `fido_cred_t` and `fido_assert_t`