feat: impl dao (#1)

Cargo.toml

migration/Cargo.toml

migration/README.md

migration/src/lib.rs

migration/src/m20220101_000001_create_table.rs

migration/src/main.rs

src/api/mod.rs

src/entity/dialog_2_kb.rs

src/entity/dialog_info.rs

src/entity/doc_2_doc.rs

src/entity/doc_info.rs

src/entity/kb_2_doc.rs

src/entity/kb_info.rs

src/entity/mod.rs

src/entity/tag_2_doc.rs

src/entity/tag_info.rs

src/entity/user_info.rs

src/main.rs

src/service/mod.rs