Update development dependencies

Updating these dependencies makes it a little easier to run tests in
development against the latest versions. Rather than run the appropriate
Appraisal command, I can just run 'cucumber' (which is the command I get
when I hit <leader> t in vim with thoughtbot's dotfiles).

Gemfile.lock

@@ -8,116 +8,143 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    actionpack (4.1.1)
-      actionview (= 4.1.1)
-      activesupport (= 4.1.1)
-      rack (~> 1.5.2)
-      rack-test (~> 0.6.2)
-    actionview (4.1.1)
-      activesupport (= 4.1.1)
+    actionpack (5.1.6)
+      actionview (= 5.1.6)
+      activesupport (= 5.1.6)
+      rack (~> 2.0)
+      rack-test (>= 0.6.3)
+      rails-dom-testing (~> 2.0)
+      rails-html-sanitizer (~> 1.0, >= 1.0.2)
+    actionview (5.1.6)
+      activesupport (= 5.1.6)
       builder (~> 3.1)
-      erubis (~> 2.7.0)
-    activemodel (4.1.1)
-      activesupport (= 4.1.1)
-      builder (~> 3.1)
-    activerecord (4.1.1)
-      activemodel (= 4.1.1)
-      activesupport (= 4.1.1)
-      arel (~> 5.0.0)
-    activerecord-jdbc-adapter (1.3.15)
-      activerecord (>= 2.2)
-    activerecord-jdbcsqlite3-adapter (1.3.15)
-      activerecord-jdbc-adapter (~> 1.3.15)
-      jdbc-sqlite3 (>= 3.7.2, < 3.9)
-    activesupport (4.1.1)
-      i18n (~> 0.6, >= 0.6.9)
-      json (~> 1.7, >= 1.7.7)
+      erubi (~> 1.4)
+      rails-dom-testing (~> 2.0)
+      rails-html-sanitizer (~> 1.0, >= 1.0.3)
+    activemodel (5.1.6)
+      activesupport (= 5.1.6)
+    activerecord (5.1.6)
+      activemodel (= 5.1.6)
+      activesupport (= 5.1.6)
+      arel (~> 8.0)
+    activerecord-jdbc-adapter (51.1-java)
+      activerecord (~> 5.1.0)
+    activerecord-jdbcsqlite3-adapter (51.1-java)
+      activerecord-jdbc-adapter (= 51.1)
+      jdbc-sqlite3 (~> 3.8, < 3.30)
+    activesupport (5.1.6)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 0.7, < 2)
       minitest (~> 5.1)
-      thread_safe (~> 0.1)
       tzinfo (~> 1.1)
-    appraisal (1.0.3)
+    appraisal (2.2.0)
       bundler
       rake
       thor (>= 0.14.0)
-    arel (5.0.1.20140414130214)
-    aruba (0.5.4)
-      childprocess (>= 0.3.6)
-      cucumber (>= 1.1.1)
-      rspec-expectations (>= 2.7.0)
-    builder (3.2.2)
-    childprocess (0.5.3)
+    arel (8.0.0)
+    aruba (0.14.6)
+      childprocess (>= 0.6.3, < 0.10.0)
+      contracts (~> 0.9)
+      cucumber (>= 1.3.19)
+      ffi (~> 1.9.10)
+      rspec-expectations (>= 2.99)
+      thor (~> 0.19)
+    builder (3.2.3)
+    childprocess (0.9.0)
       ffi (~> 1.0, >= 1.0.11)
-    coffee-rails (4.0.1)
+    coffee-rails (4.2.2)
       coffee-script (>= 2.2.0)
-      railties (>= 4.0.0, < 5.0)
-    coffee-script (2.2.0)
+      railties (>= 4.0.0)
+    coffee-script (2.4.1)
       coffee-script-source
       execjs
-    coffee-script-source (1.7.0)
+    coffee-script-source (1.12.2)
+    concurrent-ruby (1.0.5)
+    concurrent-ruby (1.0.5-java)
+    contracts (0.16.0)
+    crass (1.0.4)
     cucumber (1.3.19)
       builder (>= 2.1.2)
       diff-lcs (>= 1.1.3)
       gherkin (~> 2.12)
       multi_json (>= 1.7.5, < 2.0)
       multi_test (>= 0.1.2)
-    diff-lcs (1.2.5)
-    erubis (2.7.0)
-    execjs (2.0.2)
+    diff-lcs (1.3)
+    erubi (1.7.1)
+    execjs (2.7.0)
     factory_bot (4.10.0)
       activesupport (>= 3.0.0)
-    ffi (1.9.3)
-    ffi (1.9.3-java)
+    ffi (1.9.25)
+    ffi (1.9.25-java)
     gherkin (2.12.2)
       multi_json (~> 1.3)
     gherkin (2.12.2-java)
       multi_json (~> 1.3)
-    i18n (0.7.0)
-    jdbc-sqlite3 (3.8.7)
-    jquery-rails (3.1.0)
-      railties (>= 3.0, < 5.0)
+    i18n (1.0.1)
+      concurrent-ruby (~> 1.0)
+    jdbc-sqlite3 (3.20.1)
+    jquery-rails (4.3.3)
+      rails-dom-testing (>= 1, < 3)
+      railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
-    jruby-openssl (0.9.6-java)
-    json (1.8.6)
-    json (1.8.6-java)
-    minitest (5.9.0)
-    multi_json (1.11.2)
+    jruby-openssl (0.10.1-java)
+    loofah (2.2.2)
+      crass (~> 1.0.2)
+      nokogiri (>= 1.5.9)
+    method_source (0.9.0)
+    mini_portile2 (2.3.0)
+    minitest (5.11.3)
+    multi_json (1.13.1)
     multi_test (0.1.2)
-    power_assert (0.2.3)
-    rack (1.5.5)
-    rack-test (0.6.3)
-      rack (>= 1.0)
-    railties (4.1.1)
-      actionpack (= 4.1.1)
-      activesupport (= 4.1.1)
+    nokogiri (1.8.4)
+      mini_portile2 (~> 2.3.0)
+    nokogiri (1.8.4-java)
+    power_assert (1.1.3)
+    rack (2.0.5)
+    rack-test (1.1.0)
+      rack (>= 1.0, < 3)
+    rails-dom-testing (2.0.3)
+      activesupport (>= 4.2.0)
+      nokogiri (>= 1.6)
+    rails-html-sanitizer (1.0.4)
+      loofah (~> 2.2, >= 2.2.2)
+    railties (5.1.6)
+      actionpack (= 5.1.6)
+      activesupport (= 5.1.6)
+      method_source
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
-    rake (11.1.2)
-    rspec-core (2.14.8)
-    rspec-expectations (2.14.5)
-      diff-lcs (>= 1.1.3, < 2.0)
-    rspec-mocks (2.14.6)
-    rspec-rails (2.14.2)
+    rake (12.3.1)
+    rspec-core (3.7.1)
+      rspec-support (~> 3.7.0)
+    rspec-expectations (3.7.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.7.0)
+    rspec-mocks (3.7.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.7.0)
+    rspec-rails (3.7.2)
       actionpack (>= 3.0)
-      activemodel (>= 3.0)
       activesupport (>= 3.0)
       railties (>= 3.0)
-      rspec-core (~> 2.14.0)
-      rspec-expectations (~> 2.14.0)
-      rspec-mocks (~> 2.14.0)
-    sqlite3 (1.3.9)
-    test-unit (3.0.9)
+      rspec-core (~> 3.7.0)
+      rspec-expectations (~> 3.7.0)
+      rspec-mocks (~> 3.7.0)
+      rspec-support (~> 3.7.0)
+    rspec-support (3.7.1)
+    sqlite3 (1.3.13)
+    test-unit (3.2.8)
       power_assert
     therubyrhino (2.0.4)
       therubyrhino_jar (>= 1.7.3)
-    therubyrhino_jar (1.7.4)
-    thor (0.19.1)
-    thread_safe (0.3.5)
-    thread_safe (0.3.5-java)
-    tzinfo (1.2.2)
+    therubyrhino_jar (1.7.6)
+    thor (0.20.0)
+    thread_safe (0.3.6)
+    thread_safe (0.3.6-java)
+    tzinfo (1.2.5)
       thread_safe (~> 0.1)
-    uglifier (2.5.0)
-      execjs (>= 0.3.0)
-      json (>= 1.8.0)
+    uglifier (4.1.16)
+      execjs (>= 0.3.0, < 3)
 
 PLATFORMS
   java
@@ -141,4 +168,4 @@ DEPENDENCIES
   uglifier
 
 BUNDLED WITH
-   1.16.1
+   1.16.2