Want to install docker image circleci/ruby:2.3

I am upgrading to circleci 2.0 and it requires a docker image of ruby 2.3. But I am not able to install the mentioned ruby version from the docker site as it is not available there. Can anyone help me with this?

I just did this search,

where I found this discussion,

which showed me that Ruby 2.3.6 is still available:

$ docker pull ruby:2.3.6
2.3.6: Pulling from library/ruby
f2b6b4884fc8: Pull complete 
4fb899b4df21: Pull complete 
74eaa8be7221: Pull complete 
2d6e98fe4040: Pull complete 
638a4a258268: Pull complete 
3aae84250a19: Pull complete 
16dbfde3ef5f: Pull complete 
Digest: sha256:139ecd159fb74b1de1b1645b17cb7297bcdacee92aed8cdd0c1ada03eb9af994
Status: Downloaded newer image for ruby:2.3.6
$ docker run ruby:2.3.6 ruby -v
ruby 2.3.6p384 (2017-12-14 revision 61254) [x86_64-linux]