Modernize the project root

* Use a Gemfile / .gemspec file for bunder;
* Drop the extension of Rakefile.rb to follow current conventions;
* Drop now useless tooling from the Rakefile;
* Make the version of the gem available from the code.

These changes are supposed to introduce no functional change, and are
intended to make it easier to manage the module code.

Author: smortex

.gitignore

@@ -1,3 +1,4 @@
+Gemfile.lock
 pkg/
 ._*
 *~

Gemfile

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+source 'https://rubygems.org'
+
+# Specify your gem's dependencies in riemann-postgresql.gemspec
+gemspec

Rakefile

@@ -0,0 +1,10 @@
+require 'riemann/tools/postgresql/version'
+require 'bundler/gem_tasks'
+require 'github_changelog_generator/task'
+
+GitHubChangelogGenerator::RakeTask.new :changelog do |config|
+  config.user = 'riemann'
+  config.project = 'riemann-postgresql'
+  config.exclude_labels = ['skip-changelog']
+  config.future_release = "v#{Riemann::Tools::Postgresql::VERSION}"
+end

Rakefile.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+module Riemann
+  module Tools
+    class Postgresql
+      VERSION = '0.1.1'
+    end
+  end
+end

lib/riemann/tools/postgresql/version.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+require_relative 'lib/riemann/tools/postgresql/version'
+
+Gem::Specification.new do |spec|
+  spec.name          = 'riemann-postgresql'
+  spec.version       = Riemann::Tools::Postgresql::VERSION
+  spec.authors       = ['Pradeep Chhetri']
+  spec.email         = ['[email protected]']
+
+  spec.summary       = 'PostgreSQL Riemann Client'
+  spec.homepage      = 'https://github.com/riemann/riemann-postgresql'
+  spec.license       = 'MIT'
+  spec.required_ruby_version = Gem::Requirement.new('>= 2.6.0')
+
+  spec.metadata['allowed_push_host'] = 'https://rubygems.org/'
+
+  spec.metadata['homepage_uri']    = spec.homepage
+  spec.metadata['source_code_uri'] = spec.homepage
+  spec.metadata['changelog_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(__dir__)) do
+    `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
+  end
+  spec.bindir        = 'bin'
+  spec.executables   = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
+  spec.require_paths = ['lib']
+
+  spec.add_runtime_dependency 'pg', '>= 0.17.1'
+  spec.add_runtime_dependency 'riemann-tools', '>= 0.2.1'
+
+  spec.add_development_dependency 'github_changelog_generator'
+  spec.add_development_dependency 'rake'
+  spec.add_development_dependency 'rspec'
+  spec.add_development_dependency 'rubocop'
+  spec.add_development_dependency 'rubocop-rake'
+  spec.add_development_dependency 'rubocop-rspec'
+end