update bottle bokeh post

Author: mattmakai

README.md

@@ -7,6 +7,7 @@ Posts and associated code:
 
 |Post|Code Directory|Notes|
 |---|---|---|
+|[Creating Bar Chart Visuals with Bokeh, Bottle and Python 3](https://www.fullstackpython.com/blog/python-bottle-bokeh-bar-charts.html)|[bar-charts-bokeh-bottle-python-3](https://github.com/fullstackpython/blog-code-examples/tree/master/bar-charts-bokeh-bottle-python-3)||
 |[How to Add Hosted Monitoring to Flask Web Applications](https://www.fullstackpython.com/blog/hosted-monitoring-flask-web-apps.html)|[monitor-flask-apps](https://github.com/fullstackpython/blog-code-examples/tree/master/monitor-flask-apps)||
 |[Responsive Bar Charts with Bokeh, Flask and Python 3](https://www.fullstackpython.com/blog/responsive-bar-charts-bokeh-flask-python-3.html)|[bar-charts-bokeh-flask-python-3](https://github.com/fullstackpython/blog-code-examples/tree/master/bar-charts-bokeh-flask-python-3)||
 |[How to Create Your First Python 3.6 AWS Lambda Function](https://www.fullstackpython.com/blog/aws-lambda-python-3-6.html)|[aws-lambda-python-3-6](https://github.com/fullstackpython/blog-code-examples/tree/master/aws-lambda-python-3-6)||

bar-charts-bokeh-bottle-python-3/app.py

@@ -51,8 +51,19 @@ def chart(num_bars):
 
 
 def create_hover_tool():
-    # we'll code this function in a moment
-    return None
+    """Generates the HTML for the Bokeh's hover data tool on our graph."""
+    hover_html = """
+      <div>
+        <span class="hover-tooltip">$x</span>
+      </div>
+      <div>
+        <span class="hover-tooltip">@bugs bugs</span>
+      </div>
+      <div>
+        <span class="hover-tooltip">$@costs{0.00}</span>
+      </div>
+    """
+    return HoverTool(tooltips=hover_html)
 
 
 def create_bar_chart(data, title, x_name, y_name, hover_tool=None,