add guide for using mkcert

Author: tayloraswift

Guides/GeneratingCertificates.md

@@ -0,0 +1,41 @@
+# Generating TLS certificates
+
+To simplify the implementation and facilitate testing, Unidoc uses TLS (HTTPS) everywhere, even when running locally.
+
+For a seamless development experience, we recommend using [mkcert](https://github.com/FiloSottile/mkcert) to generate a local certificate authority (CA) for your development environment.
+
+## Installing mkcert
+
+The easiest way to install `mkcert` is to download one of its prebuilt binaries.
+
+```bash
+$ curl -JLO "https://dl.filippo.io/mkcert/latest?for=linux/amd64"
+chmod +x mkcert-v*-linux-amd64
+```
+
+## Generating a local certificate authority
+
+```bash
+$ ./mkcert-v1.4.4-linux-amd64 -install
+``````
+
+## Generating a local certificate
+
+If the `mkcert-v1.4.4-linux-amd64` binary is located in your home directory, you can generate a certificate for `localhost` by running the following from the repository root:
+
+```bash
+$ cd TestCertificates
+$ ~/mkcert-v1.4.4-linux-amd64 localhost
+
+```
+
+Then, rename the generated files to `fullchain.pem` and `privkey.pem`.
+
+```bash
+$ mv localhost.pem fullchain.pem
+$ mv localhost-key.pem privkey.pem
+```
+
+You should now be able to run the Unidoc server locally and access it without browser warnings.
+
+Keep in mind that the certificate is only valid for `localhost`; hostnames like `0.0.0.0` will still raise browser warnings.

README.md

@@ -104,6 +104,8 @@ Unidoc is tightly-integrated with Swiftinit, but you can run it locally to previ
 
 Unidoc uses [MongoDB](https://www.mongodb.com/) to persist documentation. This allows for fast startup times as Unidoc performs almost no initialization, but requires you to have an active MongoDB replica set running on your local machine. See [`Testing.md`](Guides/Testing.md) for instructions on setting up a local environment.
 
+Unidoc uses HTTPS everywhere. See [`GeneratingCertificates.md`](Guides/GeneratingCertificates.md) for how to generate a local and certificate and certificate authority for `localhost`.
+
 TODO: Add example for running the Unidoc server locally.
 
 TODO: Add example for invoking the Unidoc compiler.