readme: Fill with content

Fixes #44 (closed).

README.md

 
 # PyI40AAS – Python Industry 4.0 Asset Administration Shell
 
-The PyI40AAS project aims to provide an implementation of the Asset Administration Shell for Industry 4.0 Systems, compliant
+The PyI40AAS project aims to provide an implementation of the Asset Administration Shell (AAS) for Industry 4.0 Systems, compliant
 with the meta model and interface specification provided in
 [the document “Details of the Asset Administration Shell” (v2.0)](https://www.plattform-i40.de/PI40/Redaktion/DE/Downloads/Publikation/Details-of-the-Asset-Administration-Shell-Part1.html).
-The implementation will include the data model as well as interface adapters for serving, retreiving, importing and
-exporting Asset Administration Shells.
+
+
+## Features
+
+* Modelling of AASs as Python objects (according to DotAAS sec. 4)
+* (De-)serialization of AAS objects into/from JSON and XML (according to DotAAS sec. 5) 
+* Reading and writing of AASX package files (according to DotAAS sec. 7)
+* Storing of AAS objects in CouchDB
+* Compliance checking of AAS XML and JSON files
+
+
+### Project Structure
+
+The PyI40AAS project provides the `aas` Python package with 5 submodules:
+
+* `aas.model`: The AAS metamodel implemented in python
+* `aas.adapter`: Adapters for various file formats and storage backends
+* `aas.compliance_tools`: Compliance checker for AAS files
+* `aas.util`: Provides utilities
+* `aas.examples`: Example data and tutorials
 
 
 ## License
@@ -13,4 +31,114 @@ exporting Asset Administration Shells.
 The PyI40AAS project is provided under the terms of the Apache License (Version 2.0).
 
 For more information, especially considering the licenses of included third-party works, please consult the `NOTICE`
-file. 
+file.
+
+
+## Dependencies
+
+PyI40AAS requires the following Python packages to be installed for production usage:
+* `python-dateutil` (BSD 3-clause License)
+* `lxml` (BSD 3-clause License, using `libxml2` under MIT License)
+* `pyecma376-2` (Apache License v2.0)
+
+
+## Getting Started
+
+### Installation
+
+For most users, the recommended method to install is from PyPI:
+
+```python
+pip install pyi40aas
+```
+
+
+### Example
+
+The following code example shows how to create a `Submodel` with a `Property` serialize it into an XML file using PyI40AAS:
+
+Create a `Submodel`:
+```python
+from aas import model  # Import all PYI40AAS classes from the model package
+
+identifier = model.Identifier('https://acplt.org/Simple_Submodel', model.IdentifierType.IRI)
+submodel = model.Submodel(identification=identifier)
+```
+
+Create a `Property` and add it to the `Submodel`:
+```python
+# create a global reference to a semantic description of the property
+semantic_reference = model.Reference(
+    (model.Key(
+        type_=model.KeyElements.GLOBAL_REFERENCE,
+        local=False,
+        value='http://acplt.org/Properties/SimpleProperty',
+        id_type=model.KeyType.IRI
+    ),)
+)
+property = model.Property(
+    id_short='ExampleProperty',  # Identifying string of the element within the submodel namespace
+    value_type=model.datatypes.String,  # Data type of the value
+    value='exampleValue',  # Value of the property
+    semantic_id=semantic_reference  # set the semantic reference
+)
+submodel.submodel_element.add(property)
+```
+
+Serialize the `Submodel` to XML:
+```python
+import aas.adapter.xml.xml_serialization
+
+data: model.DictObjectStore[model.Identifiable] = model.DictObjectStore()
+data.add(submodel)
+with open('Simple_Submodel.xml', 'w', encoding='utf-8') as f:
+    aas.adapter.xml.xml_serialization.write_aas_xml_file(file=f, data=data)
+```
+
+
+### Examples and Tutorials
+
+For further examples and tutorials, check out the `aas.examples`-package. Here is a quick overview:
+
+* `examples.tutorial_create_simple_aas`: Create an Asset Administration Shell, containing an asset reference and a 
+submodel reference
+* `examples.tutorial_serialization_deserialization_json`: Tutorial for the serialization and deserialization of asset 
+administration shells, submodels and assets
+* `examples.tutorial_storage`: Tutorial for storing asset administration shells, submodels and assets
+
+
+## Contributing
+
+If you plan contributing code to the PyI40AAS project, please get in touch with us via E-Mail first: m.thies@plt.rwth-aachen.de
+
+
+### Codestyle and Testing
+
+Our code follows the [PEP 8 -- Style Guide for Python Code](https://www.python.org/dev/peps/pep-0008/).
+Additionally, we use [PEP 484 -- Type Hints](https://www.python.org/dev/peps/pep-0484/) throughout the code to enable type checking the code.
+
+Before submitting any changes, make sure to let `mypy` and `pycodestyle` check your code and run the unit tests with
+Python's builtin `unittest`. To install the required tools, use:
+```bash
+pip install mypy pycodestyle
+```
+
+Running all checks:
+```bash
+mypy aas test
+python -m pycodestyle --max-line-length 120 aas test
+python -m unittest
+```
+
+We aim to cover our code with test by at least 80%. To check test coverage, you can use `coverage`:
+
+```bash
+pip install coverage
+coverage run --source aas --branch -m unittest
+coverage report -m
+```
+
+
+### Contribute Code/Patches
+
+TBD