Correct Sentry env value

lib/constants.dart

@@ -18,15 +18,12 @@ const String kAppProductionUrl =
     'https://staging.invoicing.co'; // TODO remove staging
 const String kAppStagingUrl = 'https://staging.invoicing.co';
 const String kAppDemoUrl = 'https://demo.invoiceninja.com';
-
 const String kWhiteLabelUrl =
     'https://app.invoiceninja.com/buy_now/?account_key=AsFmBAeLXF0IKf7tmi0eiyZfmWW9hxMT&product_id=3';
-
 const String kAppPlansURL =
     'https://www.invoiceninja.com/invoicing-pricing-plans/';
 const String kPrivacyPolicyURL = 'https://www.invoiceninja.com/privacy-policy';
 const String kTermsOfServiceURL = 'https://www.invoiceninja.com/terms';
-
 const String kAppleStoreUrl =
     'https://itunes.apple.com/us/app/invoice-ninja/id1435514417?ls=1&mt=8';
 const String kGoogleStoreUrl =
@@ -35,6 +32,14 @@ const String kCapterralUrl = 'https://www.capterra.com/p/145215/Invoice-Ninja/';
 const String kCronsHelpUrl =
     'https://invoiceninja.github.io/selfhost.html#cron-configuration';
 
+enum AppEnvironment {
+  hosted,
+  selfhosted,
+  demo,
+  staging,
+  develop,
+}
+
 const String kSharedPrefs = 'shared_prefs';
 const String kSharedPrefAppVersion = 'app_version';
 const String kSharedPrefEmail = 'email';

lib/redux/app/app_state.dart

@@ -557,18 +557,18 @@ abstract class AppState implements Built<AppState, AppStateBuilder> {
     }
   }
 
-  String get environment {
+  AppEnvironment get environment {
     if (isHosted) {
       final url = cleanApiUrl(authState.url);
       if (url == kAppDemoUrl) {
-        return 'demo';
+        return AppEnvironment.demo;
       } else if (url == kAppStagingUrl) {
-        return 'staging';
+        return AppEnvironment.staging;
       } else {
-        return 'hosted';
+        return AppEnvironment.hosted;
       }
     } else {
-      return 'selfhosted';
+      return AppEnvironment.selfhosted;
     }
   }