Add example credentials file (#1042)

* added new credentials file

* remove slack integration

Author: lodewiges

config/credentials.yml.enc.example

@@ -0,0 +1,48 @@
+# Using this Medium blogpost as an example, we save all our credentials in here!
+# https://medium.com/craft-academy/encrypted-credentials-in-ruby-on-rails-9db1f36d8570
+
+secret_key_base: 
+
+production:
+  sentry_dsn: 
+  smtp_username: 
+  smtp_password: 
+
+  amber_host: 
+  sofia_host: 
+  amber_client_id: 
+  amber_client_secret: 
+
+  sumup_affiliate_key:
+  mollie_api_key:
+
+  healthcheck_ids:
+    sidekiq:
+    credit_insufficient:
+    payment_poll:
+
+staging:
+  sentry_dsn: 
+
+  amber_host: 
+  sofia_host: 
+  amber_client_id: 
+  amber_client_secret: 
+
+  sumup_affiliate_key: 
+  mollie_api_key: 
+
+development:
+
+  amber_host: localhost:4200
+  sofia_host: localhost
+  # Use amber_client_id and _secret from ENV file for your local machine
+  #  mollie_api_key: 
+
+test:
+  amber_host: localhost:4200
+  sofia_host: localhost
+  amber_client_id: 
+  amber_client_secret: 
+
+  mollie_api_key: