add build script

cowput/build.sh

@@ -0,0 +1,22 @@
+#!/bin/sh
+set -e
+
+mkdir -p bin
+
+build_targets="windows/amd64 linux/amd64 darwin/amd64"
+build_filename="cowput"
+
+for build_target in $build_targets ; do
+    build_os=$(echo "$build_target" | cut -d'/' -f1)
+    build_arch=$(echo "$build_target" | cut -d'/' -f2)
+
+    build_outfile="./bin/${build_filename}-${build_os}-${build_arch}"
+    if [ "$build_target" = "windows/amd64" ]; then
+        build_outfile="./bin/${build_filename}.exe"
+    elif [ "$build_os" = "darwin" ]; then
+        build_outfile="./bin/${build_filename}-osx-${build_arch}"
+    fi
+    echo "building ${build_outfile}"
+    GOOS=$build_os GOARCH=$build_arch go build -ldflags "$build_ldflags" -o "$build_outfile"
+done
+echo "done!"