Added example in README

Signed-off-by: Matteo Cafasso <noxdafox@gmail.com>

README.rst

@@ -13,8 +13,49 @@ The CLIPS shared library and headers must be installed within the system.
 
 If library and headers are not in the system default locations, they can be specified to the installer via the ``CFLAGS`` and ``LDFLAGS`` environment variables.
 
-::
+.. code:: bash
 
     # CFLAGS="-I<headers path>" LDFLAGS="-L<library path>" pip install pyclips
 
+Example
+-------
+
+.. code:: python
+
+    from clips import Environment, Symbol
+
+    environment = Environment()
+
+    # load constructs into the environment
+    environment.load('constructs.clp')
+
+    # assert a fact as string
+    environment.facts.assert_string('(a-fact)')
+
+    # retrieve a fact template
+    template = environment.facts.find_template('a-fact')
+
+    # create a new fact from the template
+    fact = template.new_fact()
+
+    # implied (ordered) facts are accessed as lists
+    fact.append(42)
+    fact.extend(("foo", "bar"))
+
+    # assert the fact within the environment
+    fact.assertit()
+
+    # retrieve another fact template
+    template = environment.facts.find_template('another-fact')
+    fact = template.new_fact()
+
+    # template (unordered) facts are accessed as dictionaries
+    fact["slot-name"] = Symbol("foo")
+
+    fact.assertit()
+
+    # execute the activations in the agenda
+    environment.agenda.run()
+
+
 .. _CLIPS: http://www.clipsrules.net/