updated generate forcing to show what is in the object

Author: MarkMelotto

book/some_content/generate_forcing.md

@@ -27,3 +27,10 @@ eWaterCycle supports different types of forcings, currently it supports:
 * WflowForcing
 
 The type of forcing needed is model dependent!
+
+The forcing object in eWaterCycle has some properties:
+- start time
+- end time
+- directory, which is a path
+- shapefile, also a path pointing to the shapefile, it also needs the accompanying files (so .shp + .cpg, .prj, .dbf, .shx)
+- filenames, a dictionary containing the paths to the netCDF files where the data is stored for that variable