diff --git a/.gitignore b/.gitignore
index 0e6ca9a..30b4c81 100644
--- a/.gitignore
+++ b/.gitignore
@@ -24,6 +24,7 @@
 /public/assets/
 /.byebug_history
 /.rake_tasks~
+/coverage/
 
 # Ignore master key for decrypting credentials and more.
 /config/master.key
diff --git a/.simplecov b/.simplecov
new file mode 100644
index 0000000..14b99e3
--- /dev/null
+++ b/.simplecov
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+SimpleCov.start 'rails' do
+  add_filter '/spec/'
+
+  add_group 'Channels', '/app/channels/'
+end
diff --git a/Gemfile b/Gemfile
index eceb62b..5d830ac 100644
--- a/Gemfile
+++ b/Gemfile
@@ -58,3 +58,9 @@ group :development do
   gem 'spring'
   gem 'spring-watcher-listen', '~> 2.0.0'
 end
+
+group :test do
+  # Code coverage for Ruby 1.9+ with a powerful configuration library
+  # and automatic merging of coverage across test suites.
+  gem 'simplecov', '~> 0.16', require: false
+end
diff --git a/Gemfile.lock b/Gemfile.lock
index 60ce644..384805b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -53,6 +53,7 @@ GEM
     concurrent-ruby (1.1.3)
     crass (1.0.4)
     diff-lcs (1.3)
+    docile (1.3.1)
     erubi (1.7.1)
     execjs (2.7.0)
     ffi (1.9.25)
@@ -61,6 +62,7 @@ GEM
     i18n (1.1.1)
       concurrent-ruby (~> 1.0)
     jaro_winkler (1.5.1)
+    json (2.1.0)
     listen (3.1.5)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
@@ -162,6 +164,11 @@ GEM
       sprockets (>= 2.8, < 4.0)
       sprockets-rails (>= 2.0, < 4.0)
       tilt (>= 1.1, < 3)
+    simplecov (0.16.1)
+      docile (~> 1.1)
+      json (>= 1.8, < 3)
+      simplecov-html (~> 0.10.0)
+    simplecov-html (0.10.2)
     spring (2.0.2)
       activesupport (>= 4.2)
     spring-watcher-listen (2.0.1)
@@ -208,6 +215,7 @@ DEPENDENCIES
   rspec-rails (~> 3.8)
   rubocop (~> 0.60.0)
   sass-rails (~> 5.0)
+  simplecov (~> 0.16)
   spring
   spring-watcher-listen (~> 2.0.0)
   turbolinks (~> 5)
diff --git a/spec/rails_helper.rb b/spec/rails_helper.rb
index c5d9a65..fcfaf33 100644
--- a/spec/rails_helper.rb
+++ b/spec/rails_helper.rb
@@ -1,5 +1,8 @@
 # frozen_string_literal: true
 
+# This should be on the top of the file.
+require 'simplecov'
+
 # This file is copied to spec/ when you run 'rails generate rspec:install'
 require 'spec_helper'
 ENV['RAILS_ENV'] ||= 'test'
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 6faa1fd..795e596 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,5 +1,8 @@
 # frozen_string_literal: true
 
+# This should be on the top of the file.
+require 'simplecov'
+
 # This file was generated by the `rails generate rspec:install` command.
 # Conventionally, all specs live under a `spec` directory, which RSpec adds
 # to the `$LOAD_PATH`. The generated `.rspec` file contains