adding a README file

Author: rbonifacio

README.md

@@ -0,0 +1,20 @@
+## JUnit 5 migrations
+
+A set of Rascal transformations for helping
+developers to migrate JUnit 4 test cases to JUnit 5.
+
+### Requirements
+
+   * Python 3
+   * Java 8
+
+### Build and run
+
+   * Clone this repository (`git clone [email protected]:PAMunb/JUnit5Migration.git`)
+   * Change to the JUnit5Migration folder (`cd JUnit5Migration`) 
+   * Download the Rascal shell (`wget https://update.rascal-mpl.org/console/rascal-shell-stable.jar`)
+   * Execute the `driver.py` script:
+
+```shell
+$ python3 driver.py -i <PATH_TO_GIT_REPOSITORY> -m <MAX_NUMBER_OF_FILES>
+```