Bump capybara

Gemfile

@@ -283,7 +283,7 @@ group :test do
 
   # Cucumber (integration tests)
 
-  gem "capybara",           "2.14.4"
+  gem "capybara",           "2.15.1"
   gem "database_cleaner",   "1.6.1"
   gem "poltergeist",        "1.15.0"
 

Gemfile.lock

@@ -71,9 +71,9 @@ GEM
     buftok (0.2.0)
     builder (3.2.3)
     byebug (9.0.6)
-    capybara (2.14.4)
+    capybara (2.15.1)
       addressable
-      mime-types (>= 1.16)
+      mini_mime (>= 0.1.3)
       nokogiri (>= 1.3.3)
       rack (>= 1.0.0)
       rack-test (>= 0.5.4)
@@ -373,6 +373,7 @@ GEM
       mime-types-data (~> 3.2015)
     mime-types-data (3.2016.0521)
     mini_magick (4.8.0)
+    mini_mime (0.1.4)
     mini_portile2 (2.2.0)
     minitest (5.10.3)
     mobile_fu (1.4.0)
@@ -771,7 +772,7 @@ DEPENDENCIES
   autoprefixer-rails (= 7.1.2.4)
   bootstrap-sass (= 3.3.7)
   bootstrap-switch-rails (= 3.3.3)
-  capybara (= 2.14.4)
+  capybara (= 2.15.1)
   carrierwave (= 1.1.0)
   compass-rails (= 3.0.2)
   configurate (= 0.3.1)