Support multi-table on Array
Add GrnMini::create_or_open, tmpdb
Fix column name of Terms
Add test_multi_table_select
Delete Util::create_or_open
Change & Remove Array method

Array.new(database_name) -> Array.new(table_name)
Array.tmpdb
Add Array#setup_columns
Support Groonga::Table in setup_columns
Support VECTOR_COLUMN in setup_columns
Add test_setup_columns_vector2
Add test_tweet
Add NotSupportColumnType error
Extract GrnMini::Table
Hash < Table
Tweak code
elements -> element
Bug fix
Add test_select_table_element
Add test_select_table_elements
Add test_users_and_articles