Updated gems as in issue #805 suggested.

Gemfile.lock

@@ -46,7 +46,7 @@ GEM
       tzinfo (~> 1.1)
     addressable (2.4.0)
     arel (6.0.3)
-    argon2 (1.1.1)
+    argon2 (1.1.3)
       ffi (~> 1.9)
       ffi-compiler (~> 0.1)
     ast (2.3.0)
@@ -110,7 +110,7 @@ GEM
       dnsruby (>= 1.5)
     equalizer (0.0.10)
     erubis (2.7.0)
-    eventmachine (1.2.0.1)
+    eventmachine (1.2.3)
     execjs (2.7.0)
     factory_girl (4.8.0)
       activesupport (>= 3.0.0)
@@ -121,7 +121,7 @@ GEM
       multipart-post (>= 1.2, < 3)
     faraday-http-cache (1.3.1)
       faraday (~> 0.8)
-    ffi (1.9.14)
+    ffi (1.9.18)
     ffi-compiler (0.1.3)
       ffi (>= 1.0.0)
       rake
@@ -248,7 +248,7 @@ GEM
       omniauth-oauth (~> 1.1)
     parser (2.3.1.2)
       ast (~> 2.2)
-    pg (0.18.4)
+    pg (0.20.0)
     pluginator (1.3.0)
     power_assert (0.3.1)
     powerpack (0.1.1)
@@ -292,7 +292,7 @@ GEM
       thor (>= 0.18.1, < 2.0)
     rainbow (2.1.0)
     raindrops (0.17.0)
-    rake (11.2.2)
+    rake (12.0.0)
     rb-fsevent (0.9.7)
     rb-inotify (0.9.7)
       ffi (>= 0.5.0)