Bump capybara from 2.17.0 to 2.18.0 (#88)

Bumps [capybara](https://github.com/teamcapybara/capybara) from 2.17.0 to 2.18.0.
- [Changelog](https://github.com/teamcapybara/capybara/blob/master/History.md)
- [Commits](https://github.com/teamcapybara/capybara/compare/2.17.0...2.18.0)

Gemfile

@@ -37,7 +37,7 @@ end
 
 group :development, :test do
   gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
-  gem 'capybara', '~> 2.17'
+  gem 'capybara', '~> 2.18'
   gem 'factory_bot_rails', '~> 4.8.2'
   gem 'faker', '~> 1.8'
   gem 'selenium-webdriver'

Gemfile.lock

@@ -75,7 +75,7 @@ GEM
       sass (>= 3.5.2)
     builder (3.2.3)
     byebug (10.0.0)
-    capybara (2.17.0)
+    capybara (2.18.0)
       addressable
       mini_mime (>= 0.1.3)
       nokogiri (>= 1.3.3)
@@ -180,16 +180,16 @@ GEM
     mocha (1.3.0)
       metaclass (~> 0.0.1)
     nio4r (2.1.0)
-    nokogiri (1.8.1)
+    nokogiri (1.8.2)
       mini_portile2 (~> 2.3.0)
     orm_adapter (0.5.0)
     paranoia (2.4.0)
       activerecord (>= 4.0, < 5.2)
     pg (0.21.0)
     popper_js (1.12.5)
-    public_suffix (3.0.1)
+    public_suffix (3.0.2)
     puma (3.11.2)
-    rack (2.0.3)
+    rack (2.0.4)
     rack-cors (1.0.2)
     rack-proxy (0.6.3)
       rack
@@ -297,7 +297,7 @@ DEPENDENCIES
   attr_encrypted (~> 3.0)!
   aws-sdk (~> 2.10)
   byebug
-  capybara (~> 2.17)
+  capybara (~> 2.18)
   delayed_job_active_record (~> 4.1.2)
   devise (~> 4.4.1)
   devise_invitable (~> 1.7, >= 1.7.2)