gems: remove ruby-debug-ide

- It was included to make Rubymine happy, but nowadays Rubymine seems
to load the debugger without touching the Gemfile
- It keeps matching an invalid version when `bundle upgrade`-ing the
dependencies.

Gemfile

@@ -117,7 +117,6 @@ group :development, :test do
   gem 'pry-byebug' # Call 'byebug' anywhere in the code to stop execution and get a debugger console
   gem 'rspec_junit_formatter', require: false
   gem 'rspec-rails'
-  gem 'ruby-debug-ide', require: false
   gem 'simple_xlsx_reader'
   gem 'spring' # Spring speeds up development by keeping your application running in the background
   gem 'spring-commands-rspec'

Gemfile.lock

@@ -619,8 +619,6 @@ GEM
       rubocop-rails (~> 2.0)
     rubocop-rspec-focused (1.0.0)
       rubocop (>= 0.51)
-    ruby-debug-ide (0.7.2)
-      rake (>= 0.8.1)
     ruby-graphviz (1.2.5)
       rexml
     ruby-progressbar (1.11.0)
@@ -861,7 +859,6 @@ DEPENDENCIES
   rubocop
   rubocop-rails_config
   rubocop-rspec-focused
-  ruby-debug-ide
   ruby-saml-idp
   sanitize-url
   sassc-rails