diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
new file mode 100644
index 0000000..1c2e19a
--- /dev/null
+++ b/.github/workflows/main.yml
@@ -0,0 +1,25 @@
+name: Ruby
+
+on: ['push']
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    name: Ruby ${{ matrix.ruby }}
+    strategy:
+      matrix:
+        ruby: ['2.7', '3.0', '3.1', '3.2', '3.3', 'head']
+        rubyopt: ['']
+        include:
+          - ruby: '3.3'
+            rubyopt: "--enable-frozen-string-literal --debug-frozen-string-literal"
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby }}
+        bundler-cache: true
+    - name: Run the default task
+      run: bundle exec rake RUBYOPT="${{ matrix.rubyopt }}"
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..80e3957
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+Gemfile.lock
+
diff --git a/Gemfile b/Gemfile
index 851fabc..71d74ff 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,2 +1,6 @@
 source 'https://rubygems.org'
+
 gemspec
+
+gem "rake"
+gem "rspec"
diff --git a/lib/method_source/code_helpers.rb b/lib/method_source/code_helpers.rb
index ccf054a..4185c18 100644
--- a/lib/method_source/code_helpers.rb
+++ b/lib/method_source/code_helpers.rb
@@ -90,7 +90,7 @@ def complete_expression?(str)
     # @return [String]  a valid ruby expression
     # @raise [SyntaxError]
     def extract_first_expression(lines, consume=0, &block)
-      code = consume.zero? ? "" : lines.slice!(0..(consume - 1)).join
+      code = consume.zero? ? +"" : lines.slice!(0..(consume - 1)).join
 
       lines.each do |v|
         code << v
@@ -104,7 +104,7 @@ def extract_first_expression(lines, consume=0, &block)
     # @param [Array<String>]  lines
     # @return [String]
     def extract_last_comment(lines)
-      buffer = ""
+      buffer = +""
 
       lines.each do |line|
         # Add any line that is a valid ruby comment,
@@ -112,7 +112,7 @@ def extract_last_comment(lines)
         if (line =~ /^\s*#/) || (line =~ /^\s*$/)
           buffer << line.lstrip
         else
-          buffer.replace("")
+          buffer.clear
         end
       end
 
diff --git a/method_source.gemspec b/method_source.gemspec
index 8acb290..a400823 100644
--- a/method_source.gemspec
+++ b/method_source.gemspec
@@ -16,19 +16,4 @@ Gem::Specification.new do |s|
   s.licenses = ["MIT".freeze]
   s.summary = "retrieve the sourcecode for a method".freeze
   s.test_files = ["spec/method_source/code_helpers_spec.rb".freeze, "spec/method_source_spec.rb".freeze, "spec/spec_helper.rb".freeze]
-
-  if s.respond_to? :specification_version then
-    s.specification_version = 4
-
-    if Gem::Version.new(Gem::VERSION) >= Gem::Version.new('1.2.0') then
-      s.add_development_dependency(%q<rspec>.freeze, ["~> 3.6"])
-      s.add_development_dependency(%q<rake>.freeze, ["~> 0.9"])
-    else
-      s.add_dependency(%q<rspec>.freeze, ["~> 3.6"])
-      s.add_dependency(%q<rake>.freeze, ["~> 0.9"])
-    end
-  else
-    s.add_dependency(%q<rspec>.freeze, ["~> 3.6"])
-    s.add_dependency(%q<rake>.freeze, ["~> 0.9"])
-  end
 end