Merge pull request #23 from sparkfabrik/hotfix/optional_env_matchfile

Conditional app_identifier

Author: edodusi

fastlane/Matchfile

@@ -4,7 +4,7 @@ storage_mode("git")
 
 type(ENV["MATCH_BUILD_TYPE"]) # The default type, can be: appstore, adhoc, enterprise or development
 
-app_identifier(ENV["IOS_APP_ID"])
+app_identifier(ENV["IOS_APP_ID"]) if ENV["IOS_APP_ID"]
 
 keychain_name('ios-build.keychain')
 keychain_password('12345678')