feat: adding install script for ci [skip-ci]

Author: sunggun-yu

install.sh

@@ -0,0 +1,71 @@
+#!/bin/sh
+set -e
+
+if [ "$(uname)" = "Darwin" ] ; then
+  OS="darwin"
+else
+  OS="linux"
+fi
+
+LOCAL_ARCH=$(uname -m)
+
+case "${LOCAL_ARCH}" in
+  x86_64|amd64)
+    ARCH=amd64
+    ;;
+  armv8*|aarch64*|arm64)
+    ARCH=arm64
+    ;;
+  *)
+    echo "This system's architecture, ${LOCAL_ARCH}, isn't supported"
+    exit 1
+    ;;
+esac
+
+RELEASES_URL="https://github.com/sunggun-yu/gh-app-access-token/releases"
+FILE_BASENAME="gh-app-access-token"
+
+test -z "$VERSION" && VERSION="$(curl -sfL -o /dev/null -w %{url_effective} "$RELEASES_URL/latest" |
+  grep -o 'releases/tag/v[0-9]*.[0-9]*.[0-9]*' |
+  awk -F '/' '{ print $3}')"
+
+test -z "$VERSION" && {
+  echo "Unable to get gh-app-access-token version." >&2
+  exit 1
+}
+
+test -z "$INSTALL_PATH" && INSTALL_PATH=/tmp
+
+if ! test -d "$INSTALL_PATH" ; then
+  echo "Creating INSTALL_PATH directory $INSTALL_PATH..." >&2
+  mkdir -p $INSTALL_PATH
+fi
+
+TEMP_DIR=$(mktemp -d)
+TAR_FILE="$TEMP_DIR/${FILE_BASENAME}.tar.gz"
+
+if [ "$(uname -s)" = "Darwin" ] ; then
+  DOWNLOAD_URL="$RELEASES_URL/download/$VERSION/${FILE_BASENAME}_${OS}_all.tar.gz"
+else
+  DOWNLOAD_URL="$RELEASES_URL/download/$VERSION/${FILE_BASENAME}_${OS}_${ARCH}.tar.gz"
+fi
+
+echo "Downloading gh-app-access-token $VERSION..."
+curl -sfLo "$TAR_FILE" "$DOWNLOAD_URL"
+
+if ! test -f "$TAR_FILE"; then
+  echo "Unable to download gh-app-access-token." >&2
+  exit 1
+fi
+
+tar -xzf "$TAR_FILE" -C "$TEMP_DIR" --strip-components=1
+
+if ! test -f "$TEMP_DIR/gh-app-access-token"; then
+  echo "Unable to extract gh-app-access-token." >&2
+  exit 1
+fi
+
+mv $TEMP_DIR/gh-app-access-token $INSTALL_PATH
+rm -r $TEMP_DIR
+
+printf "gh-app-access-token has been successfully downloaded into the %s folder on your system.\n" "$INSTALL_PATH"