Cannot load such file --mechanize - ruby

Question

There is a class called ParseSearch.rb, which uses mechanize gem.
I made a new file that is used for Ruby Shoes(GUI) and I required all gems that are needed
require "mechanize"
require "rubygems"
require_relative "ParseSearch.rb"
In the terminal I installed the gem
$ gem install mechanize
Successfully installed mechanize-2.7.6
Parsing documentation for mechanize-2.7.6
Done installing documentation for mechanize after 0 seconds
1 gem installed
However, when I run the shoes.rb I get a error
Error in <unknown> line 0 | 2020-02-16 15:40:27 -0500
cannot load such file -- mechanize
.shoes/walkabout/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:59:in `require'
.shoes/walkabout/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:59:in `require'
search_shoes.rb:1:in `<main>'
.shoes/walkabout/lib/shoes.rb:353:in `eval'
.shoes/walkabout/lib/shoes.rb:353:in `visit'
.shoes/walkabout/lib/shoes.rb:139:in `show_selector'
.shoes/walkabout/lib/shoes.rb:169:in `block (4 levels) in splash'
The gem env are shown below.
RubyGems Environment:
- RUBYGEMS VERSION: 3.0.3
- RUBY VERSION: 2.6.3 (2019-04-16 patchlevel 62) [x86_64-linux]
- INSTALLATION DIRECTORY: /home/daniel/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0
- USER INSTALLATION DIRECTORY: /.gem/ruby/2.6.0
- RUBY EXECUTABLE: /.rbenv/versions/2.6.3/bin/ruby
- GIT EXECUTABLE: /usr/bin/git
- EXECUTABLE DIRECTORY: /.rbenv/versions/2.6.3/bin
- SPEC CACHE DIRECTORY: /.gem/specs
- SYSTEM CONFIGURATION DIRECTORY: /.rbenv/versions/2.6.3/etc
- RUBYGEMS PLATFORMS:
- ruby
- x86_64-linux
- GEM PATHS:
- /.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0
- /.gem/ruby/2.6.0
- GEM CONFIGURATION:
- :update_sources => true
- :verbose => true
- :backtrace => false
- :bulk_threshold => 1000
- REMOTE SOURCES:
- https://rubygems.org/
- SHELL PATH:
- /.rbenv/versions/2.6.3/bin
- /.rbenv/libexec
- /.rbenv/plugins/ruby-build/bin
- /.rbenv/shims
- /.rbenv/bin
- /usr/local/sbin
- /usr/local/bin
- /usr/sbin
- /usr/bin
- /sbin
- /bin
- /usr/games
- /usr/local/games
- /snap/bin