Add configuration guide doc

docs/configuration-guide.md

@@ -0,0 +1,42 @@
+# Configuration Guide
+
+The confd configuration file is written in [TOML](https://github.com/mojombo/toml)
+and loaded from `/etc/confd/confd.toml` by default. You can specify a different config file location via the `-config-file` command line flag.
+
+```Bash
+confd -config-file ~/confd.toml
+```
+
+> Note: You can use confd without a configuration file. See [Command Line Flags](https://github.com/kelseyhightower/confd/wiki/Command-Line-Flags).
+
+Optional:
+
+* `debug` (bool) - Enable debug logging.
+* `client_cert` (string) The cert file of the client.
+* `client_key` (string) The key file of the client.
+* `confdir` (string) - The path to confd configs. The default is /etc/confd.
+* `etcd_nodes` (array of strings) - An array of etcd cluster nodes. The default
+  is ["http://127.0.0.1:4001"].
+* `etcd_scheme` (string) - The etcd scheme to use. Must be 'http' or 'https'
+* `interval` (int) - The number of seconds to wait between calls to etcd. The
+  default is 600.
+* `noop` (bool) - Enable noop mode. Process all template resource, but don't update target config.
+* `prefix` (string) - The prefix string to prefix to keys when making calls to
+  etcd. The default is "/".
+* `quiet` (bool) - Enable quiet logging. Only error messages are printed.
+* `srv_domain` (string) - The domain to query for etcd SRV records.
+* `verbose` (bool) - Enable verbose logging.
+
+Example:
+
+```TOML
+[confd]
+confdir  = "/etc/confd"
+interval = 600
+prefix   = "/"
+etcd_nodes = [
+  "http://127.0.0.1:4001",
+]
+client_cert = "/etc/confd/ssl/client.crt"
+client_key  = "/etc/confd/ssl/client.key"
+```