fixup! Update to support up through Rails 5.2

.travis.yml

@@ -7,28 +7,25 @@ rvm:
 - 2.5.9
 - 2.7.3
 gemfile:
-- gemfiles/activerecord-5.0/Gemfile.mysql2
-- gemfiles/activerecord-5.0/Gemfile.postgresql
 - gemfiles/activerecord-5.0/Gemfile.sqlite3
-- gemfiles/activerecord-5.2/Gemfile.mysql2
-- gemfiles/activerecord-5.2/Gemfile.postgresql
 - gemfiles/activerecord-5.2/Gemfile.sqlite3
-env: MYSQL_DB_USER=travis
 before_script: bundle exec rake create_databases
 after_script: bundle exec rake drop_databases
 script: bundle exec rake travis
 jobs:
   include:
-  - gemfile: gemfiles/activerecord-5.0/Gemfile.mysql
+  - gemfile: gemfiles/activerecord-5.0/Gemfile.mysql2
     services:
     - mysql
+    env: MYSQL_DB_USER=travis
   - gemfile: gemfiles/activerecord-5.0/Gemfile.postgresql
     addons:
       postgresql: '9.6'
     env: POSTGRESQL_DB_USER=postgres
-  - gemfile: gemfiles/activerecord-5.2/Gemfile.mysql
+  - gemfile: gemfiles/activerecord-5.2/Gemfile.mysql2
     services:
     - mysql
+    env: MYSQL_DB_USER=travis
   - gemfile: gemfiles/activerecord-5.2/Gemfile.postgresql
     addons:
       postgresql: '9.6'