Updated README

README.md

 # pyyaml-loaders
+
+[PyPI package page](https://pypi.org/project/pyyaml-loaders/).
+
 PyYAML loaders with enhanced functionalities.
+
+
+## Description
+
+### `IgnoreLoader`
+
+Ignore all constructors with tag `!`. Load YAML file as is.
+
+
+### `IncludeLoader`
+
+Tag: `!include`
+
+Include values from other fields in the same YAML file, or from other file, while potentially replacing a subfield in the included field with a given value.
+
+Syntax:
+```yaml
+!include [OTHER_FILE#]FIELD_TO_INCLUDE [SUBFIELD_TO_REPLACE:VALUE_TO_REPLACE_WITH]
+```
+
+
+## Installation
+
+```bash
+pip install pyyaml-loaders
+```
+
+
+## Usage
+
+In preamble:
+
+```python
+from pyyaml_loaders import IncludeLoader, IgnoreLoader
+```
+
+When loading YAML file:
+```python
+with open(yaml_file, "r") as f:
+    data = yaml.load(f, IncludeLoader)
+```
+(or `IgnoreLoader` instead of `IncludeLoader`)