add viu install script

.config/yadm/bootstrap.d/install-viu

@@ -0,0 +1,38 @@
+#!/bin/bash
+
+set -eu
+
+source "${BOOTSTRAP_LIB}/helpers"
+
+VERSION="1.4.0"
+INSTALL_DIR="${HOME}/.local/bin"
+INSTALLED_VERSION=""
+
+if [[ -x "$(command -v viu)" ]]; then
+  INSTALLED_VERSION="$(viu --version | grep -o '[0-9]\+\.[0-9]\+\.[0-9]\+')"
+fi
+
+if [[ "$VERSION" == "$INSTALLED_VERSION" ]]; then
+  echo "viu version ${VERSION} already installed."
+  exit 0
+fi
+
+echo "Installing viu version ${VERSION}..."
+
+URL="https://github.com/atanunq/viu/releases/download/v${VERSION}/viu"
+
+echo "Downloading from ${URL}..."
+TARGET="$(download "$URL")"
+
+if [[ -f "${INSTALL_DIR}/viu" ]]; then
+  echo "Removing old viu command..."
+  rm -f "${INSTALL_DIR}/viu"
+fi
+
+echo "Installing viu command to ${INSTALL_DIR}..."
+mkdir -p "${INSTALL_DIR}"
+cp "${TARGET}" "${INSTALL_DIR}/viu"
+chmod +x "${INSTALL_DIR}/viu"
+
+echo "Removing ${TARGET}..."
+rm -f "${TARGET}"