fixxed the lowercase in the function call, compare issue #120

closes #120

README.md

@@ -23,7 +23,7 @@ The **ProjectID** is your custom project number, it well be the prefix of the ID
 `PlotID` works in two Steps:
 
 1. Tag the plot
-`[figs, IDs] = PlotId.TagPlot(figs, options)`
+`[figs, IDs] = PlotID.TagPlot(figs, options)`
 
 2. Publish the plot and the associated data
 `PlotID.Publish(DataPaths,scriptPath,  figure, options)`