Added new environment variables for custom css, custom title, and custom description.

Fully tested using the Dockerfile, example can be found on https://fileshare.thenextweb.co.za

server/config.js

@@ -168,6 +168,16 @@ const conf = convict({
     default: 'https://send.firefox.com',
     env: 'BASE_URL'
   },
+  custom_title: {
+	format: String,
+	default: 'Send',
+	env: 'CUSTOM_TITLE'
+  },
+  custom_description: {
+	format: String,
+	default: 'Encrypt and send files with a link that automatically expires to ensure your important documents don’t stay online forever.',
+	env: 'CUSTOM_DESCRIPTION'
+  },
   detect_base_url: {
     format: Boolean,
     default: false,
@@ -303,7 +313,12 @@ const conf = convict({
       format: String,
       default: '',
       env: 'UI_CUSTOM_ASSETS_WORDMARK'
-    }
+    },
+	custom_css: {
+	  format: String,
+	  default: '',
+	  env: 'UI_CUSTOM_CSS'
+	}
   }
 });