Add docs for minder CLI configuration (#2031)

docs/docs/how-to/configuration.md

@@ -0,0 +1,51 @@
+---
+title: Minder CLI configuration
+sidebar_position: 80
+---
+
+# Minder CLI configuration
+
+The Minder CLI application is configured using a YAML file. The default location for the configuration file
+is `$PWD/config.yaml`. You can specify a different location using the `--config` flag. If there's no configuration 
+file at the specified location, the CLI application will use its default values.
+
+## Prerequisites
+
+* The `minder` CLI application
+* A Stacklok account
+
+## Configuration file example
+
+Below is an example configuration file. The `grpc_server` section configures the gRPC server that the CLI
+application will connect to. The `identity` section configures the issuer URL and client ID for the
+Stacklok Identity service.
+
+```yaml
+---
+# Minder CLI configuration
+# gRPC server configuration
+grpc_server:
+  host: "127.0.0.1"
+  port: 8090
+
+identity:
+  cli:
+    issuer_url: http://localhost:8081
+    client_id: minder-cli
+---
+```
+
+## Handle multiple contexts using a configuration file 
+
+The Minder CLI can be configured to use multiple contexts. A context is a set of configuration values that
+are used to define a context, i.e. connect to a specific Minder server. For example, you may have a context for your local
+development environment, a context for your staging environment, and a context for your production
+environment. You can also specify things like the default `provider`, `project` or preferred format `output`
+for each of those.
+
+To create a new context, create a new configuration file and specify it through the `--config` flag when running the
+CLI application. For example, you can create your staging configuration in `config-staging.yaml` and use it:
+
+```bash
+minder auth login --config ./config-staging.yaml
+```