feat: 초기 프로젝트 설정 및 룰.md 파일 추가

api.hyungi.net/node_modules/js-git/doc/mixins/fs-db.md

@@ -0,0 +1,53 @@
+
+# Filesystem Git Database
+
+JSGit repositories need `loadAs`, `saveAs`, `loadRaw`, `saveRaw`, `readRef`, and
+`updateRef` methods.
+Depending on the backing storage, there are various ways to implement these
+methods.
+The implementation for in-memory storage is `js-git/mixins/mem-db`, and there
+are variants for using Github or IndexDB for storage.
+
+The `js-git/mixins/fs-db` implementation provides these methods as well, but
+depends on a file system interface providing `readFile`, `readChunk`,
+`writeFile`, and `readDir`.
+These file system methods are implemented by the `git-fs-db` and
+`git-chrome-db` packages.
+
+For the purpose of this document, `=>` implies that the function does not block
+and accepts a Node.js-style callback.
+The arrow points to the type of the result.
+None of these methods need to return a continuable if the nodeback is missing.
+
+The type `binary` stands for whatever binary representation is appropriate for
+the underlying platform.
+For browsers, binary is a `Uint8Array`.
+For Node.js, binary is a `Buffer`.
+
+## readFile(path) => binary | undefined
+
+Reads the entirety of the file at the given path and produces the binary.
+If the file does not exist, readFile provides `undefined` instead.
+
+## readChunk(path, start, end) => binary | undefined
+
+Reads a byte range of the file at the given path.
+The byte range is a half open interval, including the byte at the initial index,
+and excluding the byte at the terminal index, such that the end minus the start
+is the length of the resulting binary data.
+The end offset may be negative, in which case it should count back from the end
+of the size of the file at the path, such that the size plus the negative end is
+the positive end.
+If the file does not exist, readChunk provides `undefined` instead.
+
+## writeFile(path, binary) => undefined
+
+Writes the given bytes to the file at the given path.
+The method creates any directories leading up to the path if they do not already
+exist.
+
+## readDir(path) => array of names | undefined
+
+Reads the names of the entries in the directory at the given path.
+The names are not fully qualified paths, just the name of the entry within the
+given directory.