Add a script for generating API docs

scripts/gen-api-docs.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+# Copyright 2019 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Usage ex:
+# $ gen-docs.sh
+
+set -euo pipefail
+
+(
+      cd ts/kpt-functions
+      npm run gen-docs
+)
+git add docs/api
+git commit -m "Generate API docs"