refactoring links toJson
add Feature
fix README TODO
fix README links
add Development condition
fix README
add SQL file
fix SQL
add dcasemysql.k
add sql
fix root
remove System.p
fix schema
fix error
fix error
fix column `key` => `context_key`
fix bugs and add tree.k(cgi-script)
add addContext API
merge  dcasedb.k
fix addContext