Merge pull request #422 from esabol/patch-1

Update columns-API.md with additional clarification for sort()

docs/documentation/columns-API.md

@@ -26,7 +26,7 @@ Fetch the number of columns.
 
 ### `sort(column [integer], direction [string])`
 
-Sort the selected column. The `column` parameter should be an integer representing the column. The `direction` parameter is optional.
+Sort the selected column. The `column` parameter should be an integer representing the column, starting with zero for the first column. The `direction` parameter is optional.
 
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