Merge pull request #180 from upper/feature/rename-transaction

db.go

internal/sqladapter/collection.go

internal/sqladapter/testing/adapter.go.tpl

internal/sqladapter/testing/adapter_benchmark.go.tpl

mongo/database.go

mysql/database.go

mysql/mysql.go

mysql/tx.go

postgresql/database.go

postgresql/postgresql.go

postgresql/tx.go

ql/database.go

ql/ql.go

ql/tx.go

sqlite/database.go

sqlite/sqlite.go

sqlite/tx.go