show dashboard notice if forum is running in dev mode

public/language/en-GB/admin/general/dashboard.json

@@ -21,6 +21,7 @@
 	"upgrade-available": "<p>A new version (v%1) has been released. Consider <a href=\"https://docs.nodebb.org/en/latest/upgrading/index.html\">upgrading your NodeBB</a>.</p>",
 	"prerelease-upgrade-available": "<p>This is an outdated pre-release version of NodeBB. A new version (v%1) has been released. Consider <a href=\"https://docs.nodebb.org/en/latest/upgrading/index.html\">upgrading your NodeBB</a>.</p>",
 	"prerelease-warning": "<p>This is a <strong>pre-release</strong> version of NodeBB. Unintended bugs may occur. <i class=\"fa fa-exclamation-triangle\"></i></p>",
+	"running-in-development": "<span>Forum is running in development mode. The forum may be open to potential vulnerabilities; please contact your system administrator.</span>",
 
 	"notices": "Notices",
 	"restart-not-required": "Restart not required",

src/controllers/admin/dashboard.js

@@ -30,6 +30,14 @@ dashboardController.get = function (req, res, next) {
 					link:'/admin/extend/plugins'
 				}
 			];
+
+			if (global.env !== 'production') {
+				notices.push({
+					done: false,
+					notDoneText: '[[admin/general/dashboard:running-in-development]]'
+				});
+			}
+
 			plugins.fireHook('filter:admin.notices', notices, next);
 		}
 	}, function (err, results) {