Minor README tweaks

Author: mortensi

README.md

@@ -3,9 +3,9 @@
 Simple JSON document storage on disk. 
 
 - A Python library to organize and query JSON documents on disk, basically, with no running process.
-- Each document is stored as one file named `<key>.json`. The document key is the filename stem.
-- If you want to organize documents into different folders, use one `JsonDocStore` instance per folder. Each instance manages only the JSON files in its own directory.
-- If you want to query by a field, create an index on it. This will create an `index.json` file in the store directory. It is not required for basic operations like `insert`, `update`, `delete`, and `get`.
+- You instantiate a `JsonDocStore` object with a root directory where your JSON documents will be stored. If you want to organize documents into different folders, use one `JsonDocStore` instance per folder. Each instance manages only the JSON files in its own directory. E.g. `JsonDocStore("./data/users")` and `JsonDocStore("./data/products")`.
+- Each document is stored as a file named `<key>.json`. The document key is the filename stem.
+- If you want to query by a field, create an index on it. This will create an `index.json` file in the store directory. Currently, only exact match is supported. It is not required for basic operations like `insert`, `update`, `delete`, and `get`. The index is in-memory, not persisted to disk and is rebuilt when the store is opened. 
 
 ## Installation
 
@@ -35,7 +35,7 @@ Commands:
 - `queryby FIELD VALUE`
 - `createindex FIELD`
 - `deleteindex FIELD`
-- `insert KEY JSON_DOCUMENT`
+- `insert KEY JSON_DOCUMENT` valid keys may contain letters, digits, `.`, `_`, and `-`. No whitespace.
 - `update KEY JSON_DOCUMENT`
 - `delete KEY`
 - `exit`
@@ -73,6 +73,10 @@ jsondocstore> queryby role user
 
 ## Using from your Python application
 
+Learn the API by reading the [API reference](https://mortensi.github.io/jsondocstore/api/jsondocstore.html).
+
+Example:
+
 ```python
 from jsondocstore import JsonDocStore
 
@@ -87,17 +91,10 @@ admins = store.query_by("role", "admin")
 doc = store.get("user-1")
 ```
 
-## Data Model
-
-- `get(key)` reads `<key>.json`.
-- `insert(key, doc)` writes `<key>.json`.
-- Valid keys may contain letters, digits, `.`, `_`, and `-`. No whitespace.
-
 ## Schema
 
-`index.json` is optional.
+The schema file `index.json` is optional and required only if you want to use indexes.
 
-- `create=True` creates the directory if needed. It does not create `index.json`.
 - `index_fields` defines which fields are indexed in memory.
 - `get()`, `insert()`, `delete()`, and `list_all()` work without `index.json`.
 - `query_by()` only works when an index exists. It returns a mapping of `key -> document`. Querying without an index, or on a non-indexed field, raises an error.