Document configuration module.

README.md

@@ -83,8 +83,49 @@ Building the import module files, shared and static binaries together:
 Functional Modules
 ------------------
 
+These modules are specific to this project and their generic usage is
+questionable.
+
 ### Configuration
 
+The exact behavior of some algorithms in other modules can be changed
+via configuration parameters in this global configuration module.
+
+    (*current-month* [month])
+
+* ```month``` - valid month structure as specified in the ```month``` module
+
+Configuration parameter specifying the current month. Defaults to the
+current month derived from the current system time.
+
+    (*member-file-context* [lines])
+
+* ```lines``` - number of context lines
+
+How many lines of context are to be shown in source file
+listing. Mainly used by the member file module parser and processor.
+
+    (*member-file-check-syntax* [mode])
+
+* ```mode``` - mode symbol
+
+Configures syntax error handling when parsing member files. Known
+modes are:
+
+* ```'error``` - raises an error upon encountering error
+* ```'warning``` - displays warning and displays relevant part of
+  member file source with the offending line highlighted.
+* ```'quiet``` - supresses any error reporting
+
+Other values are invalid.
+
+    (*member-default-joined* [month])
+
+* ```month``` - valid month as produced by the ```month``` module
+
+If the member file does not contain the ```joined``` key, this value
+is substituted as a default.
+
 ### Member File
 
 ### Member Record