OK, let's try and answer this one. This is the route I went down.
First, I installed the refinerycms gem.
gem install refinerycms
I then did a:
rbenv rehash
Then I followed the guide:
refinerycms rickrockstar
Bundler complained:
Bundler could not find compatible versions for gem "refinerycms-core":
In Gemfile:
refinerycms (~> 3.0) ruby depends on
refinerycms-images (= 3.0.0) ruby depends on
refinerycms-core (= 3.0.0) ruby
refinerycms (~> 3.0) ruby depends on
refinerycms-images (= 3.0.0) ruby depends on
refinerycms-core (= 3.0.0) ruby
refinerycms (~> 3.0) ruby depends on
refinerycms-images (= 3.0.0) ruby depends on
refinerycms-core (= 3.0.0) ruby
refinerycms (~> 3.0) ruby depends on
refinerycms-images (= 3.0.0) ruby depends on
refinerycms-core (= 3.0.0) ruby
refinerycms-wymeditor (>= 1.0.6, ~> 1.0) ruby depends on
refinerycms-core (>= 3.0.0, ~> 3.0) ruby
refinerycms-acts-as-indexed (>= 1.0.0, ~> 1.0) ruby depends on
refinerycms-core (~> 2.1.0) ruby
In my gemfile, I changed the following lines:
gem 'rails', '4.2.4'
gem 'refinerycms'
gem 'refinerycms-acts-as-indexed'
gem 'refinerycms-wymeditor'
And this solved the issue.
I had to then do a:
bundle install
Then a:
rails generate refinery:cms --fresh-installation
I posted an issue on github and got the following answer from the RefineryTeam:
It looks like the culprit was refinerycms-acts-as-indexed version - it should be ~> 2.0.1 to work with Refinery 3.0.0
https://github.com/refinery/refinerycms/issues/3072
Please also see this page where things might be running more smoothly than following the guide on Refinery's website. What is to be seen there is similar to Zuhaib Ali's answer above (in a bit more details).
Hope this helps