chore: added gemspec file

cqrs-generators.gemspec

+Gem::Specification.new do |spec|
+  spec.name          = "cqrs-generators"
+  spec.version       = "0.0.1"
+  spec.authors       = ["Dean Lovett"]
+  spec.email         = ["dean.lovett@nexusmods.com"]
+
+  spec.summary       = %q{Simple generators for CQRS Commands and Queries.}
+  spec.required_ruby_version = Gem::Requirement.new(">= 2.3.0")
+  spec.metadata["homepage_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