Re-introduce Rakefile and add development_dependency on rake

Signed-off-by: Utkarsh Gupta <utkarsh@debian.org>

Author: utkarsh2102

Rakefile

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require 'bundler/gem_tasks'
+require 'rspec/core/rake_task'
+require 'rubocop/rake_task'
+
+RSpec::Core::RakeTask.new(:spec)
+RuboCop::RakeTask.new
+
+task default: %i[
+  spec
+  rubocop
+]

default.nix

@@ -5,6 +5,7 @@ let
     pkgs.xsv
     pkgs.git
     pkgs.ruby_2_7
+    pkgs.rubyPackages_2_7.rake
   ];
 
 in

iso8601.gemspec

@@ -24,6 +24,7 @@ Gem::Specification.new do |s|
   s.required_ruby_version = '>= 2.4.0'
   s.add_development_dependency 'pry', '~> 0.13.1'
   s.add_development_dependency 'pry-doc', '~> 1.1.0'
+  s.add_development_dependency 'rake', '~> 13.0'
   s.add_development_dependency 'rspec', '~> 3.9'
   s.add_development_dependency 'rubocop', '~> 0.85'
   s.add_development_dependency 'rubocop-packaging', '~> 0.1.1'