Add short-hand methods for text and blob types in MySQL

In Pg and Sqlite3, `:text` and `:binary` have variable unlimited length.
But in MySQL, these have limited length for each types (ref #21591, #21619).
This change adds short-hand methods for each text and blob types.

Example:

    create_table :foos do |t|
      t.tinyblob   :tiny_blob
      t.mediumblob :medium_blob
      t.longblob   :long_blob
      t.tinytext   :tiny_text
      t.mediumtext :medium_text
      t.longtext   :long_text
    end

1 files changed, 10 insertions, 10 deletions

diff --git a/activerecord/test/schema/mysql2_specific_schema.rb b/activerecord/test/schema/mysql2_specific_schema.rb
index 9e1fe32c2d..752572a79c 100644
--- a/activerecord/test/schema/mysql2_specific_schema.rb
+++ b/activerecord/test/schema/mysql2_specific_schema.rb
@@ -2,18 +2,18 @@ ActiveRecord::Schema.define do
   create_table :binary_fields, force: true do |t|
     t.binary :var_binary, limit: 255
     t.binary :var_binary_large, limit: 4095
-    t.blob   :tiny_blob, limit: 255
-    t.binary :normal_blob, limit: 65535
-    t.binary :medium_blob, limit: 16777215
-    t.binary :long_blob, limit: 2147483647
-    t.text   :tiny_text, limit: 255
-    t.text   :normal_text, limit: 65535
-    t.text   :medium_text, limit: 16777215
-    t.text   :long_text, limit: 2147483647
+    t.tinyblob   :tiny_blob
+    t.blob       :normal_blob
+    t.mediumblob :medium_blob
+    t.longblob   :long_blob
+    t.tinytext   :tiny_text
+    t.text       :normal_text
+    t.mediumtext :medium_text
+    t.longtext   :long_text
+
+    t.index :var_binary
   end
 
-  add_index :binary_fields, :var_binary
-
   create_table :key_tests, force: true, :options => 'ENGINE=MyISAM' do |t|
     t.string :awesome
     t.string :pizza