Merge branch 'master' into activestorage-guide

Gemfile

@@ -74,7 +74,6 @@ end
 group :cable do
   gem "puma", require: false
 
-  gem "em-hiredis", require: false
   gem "hiredis", require: false
   gem "redis", "~> 4.0", require: false
 

Gemfile.lock

@@ -216,9 +216,6 @@ GEM
       activerecord (>= 3.0, < 5.2)
       delayed_job (>= 3.0, < 5)
     digest-crc (0.4.1)
-    em-hiredis (0.3.1)
-      eventmachine (~> 1.0)
-      hiredis (~> 0.6.0)
     em-http-request (1.1.5)
       addressable (>= 2.3.4)
       cookiejar (!= 0.3.1)
@@ -232,9 +229,6 @@ GEM
       tzinfo
     event_emitter (0.2.6)
     eventmachine (1.2.5)
-    eventmachine (1.2.5-java)
-    eventmachine (1.2.5-x64-mingw32)
-    eventmachine (1.2.5-x86-mingw32)
     execjs (2.7.0)
     faraday (0.13.1)
       multipart-post (>= 1.2, < 3)
@@ -371,7 +365,7 @@ GEM
       rack (>= 0.4)
     rack-protection (2.0.0)
       rack
-    rack-test (0.7.1)
+    rack-test (0.8.0)
       rack (>= 1.0, < 3)
     rails-dom-testing (2.0.3)
       activesupport (>= 4.2.0)
@@ -523,7 +517,6 @@ DEPENDENCIES
   dalli (>= 2.2.1)
   delayed_job
   delayed_job_active_record
-  em-hiredis
   google-cloud-storage (~> 1.3)
   hiredis
   json (>= 2.0.0)