added support for DOMAIN env var insted of file

src/constants.ts

@@ -0,0 +1,15 @@
+import { paths } from './utils/files'
+import utils from './utils/utils'
+
+const domain = process.env.DOMAIN || utils.ReadFile(paths.domainFile).trim()
+
+if (!domain) {
+    throw new Error(
+        `Domain is undefined! Should be set with 'DOMAIN' environment variable, or written to '${paths.domainFile}'`
+    )
+}
+
+export default {
+    savedQuestionsFileName: 'savedQuestions.json',
+    domain: domain,
+}