add text in readme

Author: giannisdoukas

README.md

@@ -4,3 +4,24 @@
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+IPython2CWL is a tool for converting [IPython](https://ipython.org/) Jupyter Notebooks to
+[CWL](https://www.commonwl.org/) Command Line Tools by simply providing typing annotation.
+
+
+```python
+from ipython2cwl.iotypes import CWLFilePathInput, CWLFilePathOutput
+import csv
+input_filename: 'CWLFilePathInput' = 'data.csv'
+with open(input_filename) as f:
+  csv_reader = csv.reader(f)
+  data = [line for line in csv_reader]
+number_of_lines = len(data)
+result_file: 'CWLFilePathOutput' = 'number_of_lines.txt'
+with open(result_file, 'w') as f:
+  f.write(str(number_of_lines))
+```
+
+IPython2CWL is based on [repo2docker](https://github.com/jupyter/repo2docker), the same tool
+used by [mybinder](https://mybinder.org/). Now, by writing Jupyter Notebook and publish them, including repo2docker
+configuration, the community can not only execute the notebooks remotely but also to use them as steps in scientific
+workflows.