Remove the word "mongrel" from documents

Currently mongrel is not maintained.
And it couldn't be built with any Ruby versions that
supported by Rails.

It is reasonable to remove the word "mongrel" in order to avoid
confusion from newcomer.

1 files changed, 1 insertions, 1 deletions

diff --git a/guides/source/configuring.md b/guides/source/configuring.md
index a115683134..c54affb70e 100644
--- a/guides/source/configuring.md
+++ b/guides/source/configuring.md
@@ -1198,7 +1198,7 @@ development:
   timeout: 5000
 ```
 
-Since the connection pooling is handled inside of Active Record by default, all application servers (Thin, mongrel, Unicorn etc.) should behave the same. The database connection pool is initially empty. As demand for connections increases it will create them until it reaches the connection pool limit.
+Since the connection pooling is handled inside of Active Record by default, all application servers (Thin, Puma, Unicorn etc.) should behave the same. The database connection pool is initially empty. As demand for connections increases it will create them until it reaches the connection pool limit.
 
 Any one request will check out a connection the first time it requires access to the database. At the end of the request it will check the connection back in. This means that the additional connection slot will be available again for the next request in the queue.