fix missing branchName
AddPrefix and tests for common.go
remove GetSchema, because it can be integrated into GetTables
AddSuffix and ConcreteName with corresponding tests
refractor a little bit; need to complete parser before proceed on this package
sql rewriter and its tests
separate creating branch managment table from Init(); add corresponding tests for branch managment table creating and destroying
working on CreateBranch; cannot proceed until finish parser.ParseSchema
add TODOs