Fix "Specified key was too long; max key length is 1000 bytes (Mysql2::Error)"

Author: kamipo

activerecord/test/schema/mysql2_specific_schema.rb

@@ -47,7 +47,7 @@
     t.index :var_binary
   end
 
-  create_table :key_tests, force: true, options: "ENGINE=MyISAM" do |t|
+  create_table :key_tests, force: true, options: "CHARSET=utf8 ENGINE=MyISAM" do |t|
     t.string :awesome
     t.string :pizza
     t.string :snacks