Promote set to default gems

doc/maintainers.rdoc

@@ -67,8 +67,6 @@ Zachary Scott (zzak)
 [lib/rubygems.rb, lib/rubygems/*]
   Eric Hodel (drbrain), Hiroshi SHIBATA (hsbt)
   https://github.com/rubygems/rubygems
-[lib/set.rb]
-  Akinori MUSHA (knu)
 [lib/securerandom.rb]
   Tanaka Akira (akr)
 [lib/shellwords.rb]
@@ -233,6 +231,9 @@ Zachary Scott (zzak)
   aycabta
   https://github.com/ruby/reline
   https://rubygems.org/gems/reline
+[lib/set.rb]
+  Akinori MUSHA (knu)
+  https://github.com/ruby/set
 [lib/singleton.rb]
   Yukihiro Matsumoto (matz)
   https://github.com/ruby/singleton

doc/standard_library.rdoc

@@ -24,7 +24,6 @@ Resolv::  Thread-aware DNS resolver library in Ruby
 Rinda:: The Linda distributed computing paradigm in Ruby
 Gem:: Package management framework for Ruby
 SecureRandom:: Interface for secure random number generator
-Set:: Provides a class to deal with collections of unordered, unique values
 Shellwords:: Manipulates strings with word parsing rules of UNIX Bourne shell
 Time:: Extends the Time class with methods for parsing and conversion
 TSort:: Topological sorting using Tarjan's algorithm
@@ -76,6 +75,7 @@ Prime:: Prime numbers and factorization library
 PStore:: Implements a file based persistence mechanism based on a Hash
 Racc:: A LALR(1) parser generator written in Ruby.
 RDoc:: Produces HTML and command-line documentation for Ruby
+Set:: Provides a class to deal with collections of unordered, unique values
 Singleton:: Implementation of the Singleton pattern for Ruby
 Tempfile:: A utility class for managing temporary files
 Timeout:: Auto-terminate potentially long-running operations in Ruby

lib/set.gemspec

@@ -0,0 +1,24 @@
+Gem::Specification.new do |spec|
+  spec.name          = "set"
+  spec.version       = "0.1.0"
+  spec.authors       = ["Akinori MUSHA"]
+  spec.email         = ["knu@idaemons.org"]
+
+  spec.summary       = %q{Provides a class to deal with collections of unordered, unique values}
+  spec.description   = %q{Provides a class to deal with collections of unordered, unique values}
+  spec.homepage      = "https://github.com/ruby/set"
+  spec.required_ruby_version = Gem::Requirement.new(">= 2.3.0")
+  spec.licenses      = ["Ruby", "BSD-2-Clause"]
+
+  spec.metadata["homepage_uri"] = spec.homepage
+  spec.metadata["source_code_uri"] = spec.homepage
+
+  # Specify which files should be added to the gem when it is released.
+  # The `git ls-files -z` loads the files in the RubyGem that have been added into git.
+  spec.files         = Dir.chdir(File.expand_path('..', __FILE__)) do
+    `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
+  end
+  spec.bindir        = "exe"
+  spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
+  spec.require_paths = ["lib"]
+end

tool/sync_default_gems.rb

@@ -62,6 +62,7 @@ $repositories = {
   "net-http": "ruby/net-http",
   bigdecimal: "ruby/bigdecimal",
   optparse: "ruby/optparse",
+  set: "ruby/set",
 }
 
 def sync_default_gems(gem)