One WordPress wp-config.php to rule them all: Development-, Staging- and Live-Server.

wp-config.php

<?php
/*
 * One WordPress wp-config.php to rule them all: Development-, Staging- and Live-Server.
 */

// Define Environments
$environments = array(
    'dev' => 'server.dev',
    'staging' => 'staging.server.com',
    'live' => 'www.server.com',
);

// Probe Server Name
$server_name = $_SERVER['SERVER_NAME'];

foreach($environments AS $key => $env){
    if(strstr($server_name, $env)){
        define('ENVIRONMENT', $key);
        break;
    }
}
 
// If no environment is set default to production
if(!defined('ENVIRONMENT')) define('ENVIRONMENT', 'live');

// Define different wp-config details depending on environment
switch(ENVIRONMENT){
 
    case 'dev':

      define('DB_NAME',     'DBNAME');
      define('DB_USER',     'DBUSER');
      define('DB_PASSWORD', 'PASSWORD');
      define('DB_HOST',     'localhost');
      define('WP_DEBUG',    true);
      define('WP_CACHE',    false );
      break;

    case 'staging':

      define('DB_NAME',     'DBNAME');
      define('DB_USER',     'DBUSER');
      define('DB_PASSWORD', 'PASSWORD');
      define('DB_HOST',     'localhost');
      define('WP_DEBUG',    TRUE );
      define( 'WP_CACHE',   TRUE );
      break;
 
    case 'live':
      // Whatever you want to configure that´s not already set below..
      define('DB_NAME',             'DBNAME');
      define('DB_USER',             'DBUSER');
      define('DB_PASSWORD',         'PASSWORD');
      define('DB_HOST',             'localhost');
      define('WP_DEBUG',            false);
      define('WP_CACHE',            TRUE);
      define('WP_POST_REVISIONS',   '10');
      define('MEDIA_TRASH',         true);
      define('WP_MEMORY_LIMIT',     '128M');
      define('WP_MAX_MEMORY_LIMIT', '256M');
      define('COMPRESS_CSS',        true);
      define('COMPRESS_SCRIPTS',    true);
      define('CONCATENATE_SCRIPTS', true);
      define('ENFORCE_GZIP',        true);
      define('DISALLOW_FILE_EDIT',  true);
      break;
}

// Common setting for all environments after this.
$table_prefix = 'wp_';

// Language Settings
define('WPLANG', 'de_DE');

// Authentication Unique Keys and Salts. 
// {@link https://api.wordpress.org/secret-key/1.1/salt/ WordPress.org secret-key service}

define('AUTH_KEY',         'd@wJ;|o+0q;+;fp&+++j91~@t8N.4|rT?A|.LOB8q~G:hWx-3SX!B.N[amy^pwE5');
define('SECURE_AUTH_KEY',  'ggKPj9v{Z5Fd[L&~o|F8fUO>#HxEaOw=}FKpd-;!<z4yGNHjZ0|+OKz~KfDgwFM{');
define('LOGGED_IN_KEY',    '|$B:S+:!$8=,UzEP`T?E+sH6h(f|?e[E88^2<P>Q6WyZ+4kSg>trCm-oM|KAVcdE');
define('NONCE_KEY',        '89>pZ{G1Oj32MUOE[V<7z~EyP?|HO`L;dy]vK<VX+]qRadxI:4LnlL:]zsaF-1C ');
define('AUTH_SALT',        't:WsQ.R`-YcX0#Ci2p7I5>+ZZTkC6DwQa5bH-<;.&%(_.tH!+aktnYnjDe[qO`)V');
define('SECURE_AUTH_SALT', 'R2z5)gpAmZ_KL>--%~cC:US}m`]W}:ct3Rtsv-[Dj7vxk3bnKgH|rfWx6GP!oB(S');
define('LOGGED_IN_SALT',   'czRXQplk8-G1)_r}9+$sF.UU1E0A&ZFDv12+P;EMzr{bR/vg5FF>Ssvjc*of+:F#');
define('NONCE_SALT',       'uR`:MZ*rX2%RjRDCh%;)QhK-+Q_VQlN>XUh2eFZqNALJXC*fuk6IV!cIW.sO+6+L');


/* That's all, stop editing! Happy blogging. */
/** Absolute path to the WordPress directory. */
if ( ! defined( 'ABSPATH' ) )
	define( 'ABSPATH', dirname( __FILE__ ) . '/' );

/** Sets up WordPress vars and included files. */
require_once ABSPATH . 'wp-settings.php';