update development dependencies

Gemfile.lock

@@ -9,58 +9,58 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    activemodel (4.2.6)
-      activesupport (= 4.2.6)
+    activemodel (4.2.10)
+      activesupport (= 4.2.10)
       builder (~> 3.1)
-    activesupport (4.2.6)
+    activesupport (4.2.10)
       i18n (~> 0.7)
-      json (~> 1.7, >= 1.7.7)
       minitest (~> 5.1)
       thread_safe (~> 0.3, >= 0.3.4)
       tzinfo (~> 1.1)
     axiom-types (0.1.1)
       descendants_tracker (~> 0.0.4)
       ice_nine (~> 0.11.0)
       thread_safe (~> 0.3, >= 0.3.1)
-    builder (3.2.2)
+    builder (3.2.3)
     coercible (1.0.0)
       descendants_tracker (~> 0.0.1)
+    concurrent-ruby (1.0.5)
     descendants_tracker (0.0.4)
       thread_safe (~> 0.3, >= 0.3.1)
-    diff-lcs (1.2.5)
+    diff-lcs (1.3)
     docile (1.1.5)
     equalizer (0.0.11)
-    i18n (0.7.0)
+    i18n (0.9.1)
+      concurrent-ruby (~> 1.0)
     ice_nine (0.11.2)
-    json (1.8.3)
-    minitest (5.8.4)
-    rake (11.1.2)
-    rdoc (4.2.2)
-      json (~> 1.4)
-    rspec (3.4.0)
-      rspec-core (~> 3.4.0)
-      rspec-expectations (~> 3.4.0)
-      rspec-mocks (~> 3.4.0)
-    rspec-core (3.4.4)
-      rspec-support (~> 3.4.0)
-    rspec-expectations (3.4.0)
+    json (2.1.0)
+    minitest (5.10.3)
+    rake (11.3.0)
+    rdoc (4.3.0)
+    rspec (3.7.0)
+      rspec-core (~> 3.7.0)
+      rspec-expectations (~> 3.7.0)
+      rspec-mocks (~> 3.7.0)
+    rspec-core (3.7.0)
+      rspec-support (~> 3.7.0)
+    rspec-expectations (3.7.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.4.0)
-    rspec-mocks (3.4.1)
+      rspec-support (~> 3.7.0)
+    rspec-mocks (3.7.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.4.0)
-    rspec-support (3.4.1)
+      rspec-support (~> 3.7.0)
+    rspec-support (3.7.0)
     shoulda-callback-matchers (1.1.4)
       activesupport (>= 3)
-    shoulda-matchers (3.1.1)
+    shoulda-matchers (3.1.2)
       activesupport (>= 4.0.0)
-    simplecov (0.11.2)
+    simplecov (0.15.1)
       docile (~> 1.1.0)
-      json (~> 1.8)
+      json (>= 1.8, < 3)
       simplecov-html (~> 0.10.0)
-    simplecov-html (0.10.0)
-    thread_safe (0.3.5)
-    tzinfo (1.2.2)
+    simplecov-html (0.10.2)
+    thread_safe (0.3.6)
+    tzinfo (1.2.4)
       thread_safe (~> 0.1)
     virtus (1.0.5)
       axiom-types (~> 0.1)
@@ -81,4 +81,4 @@ DEPENDENCIES
   virtus_model!
 
 BUNDLED WITH
-   1.13.6
+   1.15.3