diff --git a/.rubocop.yml b/.rubocop.yml
index 56d1540..ab3522c 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -4,7 +4,7 @@ AllCops:
     - db/**/*
     - config/**/*
     - Vagrantfile
-  TargetRubyVersion: 2.3
+  TargetRubyVersion: 2.4
 
 Naming/AccessorMethodName:
   Enabled: false
diff --git a/Gemfile.lock b/Gemfile.lock
new file mode 100644
index 0000000..35b5105
--- /dev/null
+++ b/Gemfile.lock
@@ -0,0 +1,64 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    ast (2.3.0)
+    diff-lcs (1.3)
+    multi_json (1.12.2)
+    net-scp (1.2.1)
+      net-ssh (>= 2.6.5)
+    net-ssh (4.2.0)
+    net-telnet (0.1.1)
+    parallel (1.12.0)
+    parser (2.4.0.0)
+      ast (~> 2.2)
+    powerpack (0.1.1)
+    rainbow (2.2.2)
+      rake
+    rake (12.1.0)
+    rspec (3.6.0)
+      rspec-core (~> 3.6.0)
+      rspec-expectations (~> 3.6.0)
+      rspec-mocks (~> 3.6.0)
+    rspec-core (3.6.0)
+      rspec-support (~> 3.6.0)
+    rspec-expectations (3.6.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.6.0)
+    rspec-its (1.2.0)
+      rspec-core (>= 3.0.0)
+      rspec-expectations (>= 3.0.0)
+    rspec-mocks (3.6.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.6.0)
+    rspec-support (3.6.0)
+    rubocop (0.50.0)
+      parallel (~> 1.10)
+      parser (>= 2.3.3.1, < 3.0)
+      powerpack (~> 0.1)
+      rainbow (>= 2.2.2, < 3.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (~> 1.0, >= 1.0.1)
+    ruby-progressbar (1.9.0)
+    serverspec (2.41.0)
+      multi_json
+      rspec (~> 3.0)
+      rspec-its
+      specinfra (~> 2.72)
+    sfl (2.3)
+    specinfra (2.72.0)
+      net-scp
+      net-ssh (>= 2.7, < 5.0)
+      net-telnet
+      sfl
+    unicode-display_width (1.3.0)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  rake
+  rubocop (= 0.50.0)
+  serverspec
+
+BUNDLED WITH
+   1.13.6