diff --git a/.gitignore b/.gitignore
index 58b6f0b..b00c4c4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,7 +4,6 @@
 .config
 .yardoc
 .DS_Store
-Gemfile.lock
 InstalledFiles
 _yardoc
 coverage
diff --git a/Gemfile.lock b/Gemfile.lock
new file mode 100644
index 0000000..e68fa0c
--- /dev/null
+++ b/Gemfile.lock
@@ -0,0 +1,73 @@
+PATH
+  remote: .
+  specs:
+    vmstat (2.3.0)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    coderay (1.1.1)
+    diff-lcs (1.2.5)
+    ffi (1.9.14)
+    formatador (0.2.5)
+    guard (2.14.0)
+      formatador (>= 0.2.4)
+      listen (>= 2.7, < 4.0)
+      lumberjack (~> 1.0)
+      nenv (~> 0.1)
+      notiffany (~> 0.0)
+      pry (>= 0.9.12)
+      shellany (~> 0.0)
+      thor (>= 0.18.1)
+    guard-compat (1.2.1)
+    guard-rspec (4.7.3)
+      guard (~> 2.1)
+      guard-compat (~> 1.1)
+      rspec (>= 2.99.0, < 4.0)
+    listen (3.1.5)
+      rb-fsevent (~> 0.9, >= 0.9.4)
+      rb-inotify (~> 0.9, >= 0.9.7)
+      ruby_dep (~> 1.2)
+    lumberjack (1.0.10)
+    method_source (0.8.2)
+    nenv (0.3.0)
+    notiffany (0.1.1)
+      nenv (~> 0.1)
+      shellany (~> 0.0)
+    pry (0.10.4)
+      coderay (~> 1.1.0)
+      method_source (~> 0.8.1)
+      slop (~> 3.4)
+    rake (11.3.0)
+    rake-compiler (1.0.3)
+      rake
+    rb-fsevent (0.9.8)
+    rb-inotify (0.9.7)
+      ffi (>= 0.5.0)
+    rspec (2.99.0)
+      rspec-core (~> 2.99.0)
+      rspec-expectations (~> 2.99.0)
+      rspec-mocks (~> 2.99.0)
+    rspec-core (2.99.2)
+    rspec-expectations (2.99.2)
+      diff-lcs (>= 1.1.3, < 2.0)
+    rspec-mocks (2.99.4)
+    ruby_dep (1.5.0)
+    shellany (0.0.1)
+    slop (3.6.0)
+    thor (0.19.4)
+    timecop (0.8.1)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  guard-rspec
+  rake (~> 11.3)
+  rake-compiler
+  rspec (~> 2.9)
+  timecop
+  vmstat!
+
+BUNDLED WITH
+   1.13.6
diff --git a/vmstat.gemspec b/vmstat.gemspec
index 4974b58..77e7800 100644
--- a/vmstat.gemspec
+++ b/vmstat.gemspec
@@ -21,8 +21,8 @@ Gem::Specification.new do |gem|
   gem.require_paths = ["lib"]
   gem.extensions    = ["ext/vmstat/extconf.rb"]
 
-  gem.add_development_dependency('rake')
-  gem.add_development_dependency('rspec', "~> 2.9")
+  gem.add_development_dependency('rake', '~> 11.3')
+  gem.add_development_dependency('rspec', '~> 2.9')
   gem.add_development_dependency('rake-compiler')
   gem.add_development_dependency('guard-rspec')
   gem.add_development_dependency('timecop')