Add gpg_sign: false to send --no-gpg-sign to git

Signed-off-by: Bradley Buda <bradleybuda@gmail.com>

README.md

@@ -244,6 +244,9 @@ g.commit('message', gpg_sign: true)
 key_id = '0A46826A'
 g.commit('message', gpg_sign: key_id)
 
+# Skip signing a commit (overriding any global gpgsign setting)
+g.commit('message', gpg_sign: false)
+
 g = Git.clone(repo, 'myrepo')
 g.chdir do
 new_file('test-file', 'blahblahblah')

lib/git/lib.rb

@@ -647,7 +647,7 @@ def remove(path = '.', opts = {})
     #  :date
     #  :no_verify
     #  :allow_empty_message
-    #  :gpg_sign
+    #  :gpg_sign (accepts true, false, or a gpg key ID as a String)
     #
     # @param [String] message the commit message to be used
     # @param [Hash] opts the commit options to be used
@@ -661,10 +661,12 @@ def commit(message, opts = {})
       arr_opts << "--date=#{opts[:date]}" if opts[:date].is_a? String
       arr_opts << '--no-verify' if opts[:no_verify]
       arr_opts << '--allow-empty-message' if opts[:allow_empty_message]
-      if opts[:gpg_sign]
+      if opts.has_key?(:gpg_sign)
         arr_opts <<
           if opts[:gpg_sign] == true
             '--gpg-sign'
+          elsif opts[:gpg_sign] == false
+            '--no-gpg-sign'
           else
             "--gpg-sign=#{opts[:gpg_sign]}"
           end

tests/units/test_commit_with_gpg.rb

@@ -34,4 +34,18 @@ def test_with_specific_gpg_keyid
       assert_match(/commit.*--gpg-sign=keykeykey['"]/, actual_cmd)
     end
   end
+
+  def test_disabling_gpg_sign
+    Dir.mktmpdir do |dir|
+      git = Git.init(dir)
+      actual_cmd = nil
+      git.lib.define_singleton_method(:run_command) do |git_cmd, &block|
+        actual_cmd = git_cmd
+        `true`
+      end
+      message = 'My commit message'
+      git.commit(message, gpg_sign: false)
+      assert_match(/commit.*--no-gpg-sign['"]/, actual_cmd)
+    end
+  end
 end