webconfig: files for the vulndb website configuration

Add content to display at https://vuln.go.dev, and for 404s.
Add a README to show how to use it.

Change-Id: Ide5048862aeb574dfe8e8b0ec92788ad3f820198
Reviewed-on: https://go-review.googlesource.com/c/vulndb/+/410534
Run-TryBot: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Julie Qiu <julie@golang.org>
Reviewed-by: Jamal Carvalho <jamal@golang.org>
diff --git a/webconfig/404.html b/webconfig/404.html
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+++ b/webconfig/404.html
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+<!DOCTYPE html>
+<html lang="en" data-layout="">
+  <head>
+    <title>Not Found: Go Vulnerability Database</title>
+  </head>
+<body>
+  <h1>Not Found</h1>
+
+<p>
+  We couldn't find what you're looking for in the Go Vulnerability Database.
+</p>
+<p>
+  At the top level, the database is organized by module. The ID directory lists Go
+  vulnerabilities by ID.
+</p>
+<p>
+  Check out https://go.dev/security/vulndb for more information.
+</p>
+</body>
+</html>
diff --git a/webconfig/README.md b/webconfig/README.md
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+# Go Vulnerability Database Web Configuration
+
+These files control what users see when they visit https://vuln.go.dev, and
+when they get a 404 on that site.
+
+## Deployment
+
+After these files are modified and the CL has been submitted, copy them to the
+vuln DB bucket:
+```
+gsutil cp index.html 404.html gs://go-vulndb
+```
+
+## Initial Setup
+
+The go-vulndb bucket must be configured to display these pages. That can be done
+with
+```
+gsutil web set -m index.html -e 404.html gs://go-vulndb
+```
+Use `gsutil web get gs://go-vulndb` to display the configuration.
diff --git a/webconfig/index.html b/webconfig/index.html
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+++ b/webconfig/index.html
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+<!DOCTYPE html>
+<html lang="en" data-layout="">
+  <head>
+    <title>Go Vulnerability Database</title>
+  </head>
+<body>
+  <h1>Go Vulnerability Database</h1>
+
+<p>
+  This is the Go vulnerability database. It is meant to be accessed by programs
+  that want to find vulnerabilities associated with Go modules.
+</p>
+<p>
+  Check out https://go.dev/security/vulndb for more information.
+</p>
+</body>
+</html>