diff --git a/.ruby-version b/.ruby-version
new file mode 100644
index 0000000..fd2a018
--- /dev/null
+++ b/.ruby-version
@@ -0,0 +1 @@
+3.1.0
diff --git a/Gemfile b/Gemfile
index 47a30b8..0b91a83 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,6 +5,7 @@ gemspec
 
 gem "rails", require: false # only used to test the generator
 gem "wit_ruby"
+gem "webrick"
 
 # test dependencies
 gem "rspec"
diff --git a/bitbot.gemspec b/bitbot.gemspec
index 21b972a..c952aa7 100644
--- a/bitbot.gemspec
+++ b/bitbot.gemspec
@@ -17,7 +17,7 @@ Gem::Specification.new do |s|
   s.license     = "MIT"
   s.files       = Dir["{lib}/**/*"] + ["MIT.LICENSE", "README.md"]
 
-  s.required_ruby_version = "~> 2.4"
+  s.required_ruby_version = ">= 2.4"
   s.add_dependency "rack"
   s.add_dependency "redis"
   s.add_dependency "activesupport" # TODO: move to remove this.