genrating secret can be done using rails secret since rails 5

Not sure when it became not possible to use rake secret for that

Author: toy

config/credentials.yml

@@ -33,7 +33,7 @@
 
 # Make sure the secret is at least 30 characters and all random,
 # no regular words or you'll be exposed to dictionary attacks.
-# You can use `rake secret` to generate a secure secret key.
+# You can use `rails secret` to generate a secure secret key.
 
 # Make sure the secrets in this file are kept private
 # if you're sharing your code publicly.

docs/installation-and-operations/installation/manual/README.md

@@ -239,11 +239,11 @@ will seed the database in the French language.
 
 ### Secret token
 
-You need to generate a secret key base for the production environment with `./bin/rake secret` and make that available through the environment variable `SECRET_KEY_BASE`.
+You need to generate a secret key base for the production environment with `./bin/rails secret` and make that available through the environment variable `SECRET_KEY_BASE`.
 In this installation guide, we will use the local `.profile` of the OpenProject user. You may alternatively set the environment variable in `/etc/environment` or pass it to the server upon start manually in `/etc/apache2/envvars`.
 
 ```shell
-[openproject@host] echo "export SECRET_KEY_BASE=$(./bin/rake secret)" >> ~/.profile
+[openproject@host] echo "export SECRET_KEY_BASE=$(./bin/rails secret)" >> ~/.profile
 [openproject@host] source ~/.profile
 ```