Add CI

Author: tormol

.cirrus.yml

@@ -0,0 +1,15 @@
+task:
+  name: Linux amd64 nightly
+  container:
+    image: rustlang/rust:nightly
+    cpu: 1
+    memory: 1
+  setup_script:
+    - apt-get update
+    - apt-get install -yqq nasm bsdmainutils
+  build_script:
+    - ./build.sh
+  test_script:
+    - ./tinyrust
+    - test "$(./tinyrust)" == 'Hello!'
+    - test "$(wc -c < tinyrust)" -eq 137

README.md

@@ -1,5 +1,7 @@
 # Using Rust to make a 137-byte static AMD64 Linux binary
 
+[![Build Status](https://api.cirrus-ci.com/github/tormol/tiny-rust-executable.svg)](https://cirrus-ci.com/github/tormol/tiny-rust-executable)
+
 Requires nightly Rust because it uses the `sc` crate to make direct
 system calls.