Add support for logging errors during in production mode.

Add COMMON_PRODUCTION_ERROR_LOG_PATH to control path of log file.
Defaults to mayan/error.log.
Add support logging request exceptions.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/common/middleware/error_logging.py

@@ -0,0 +1,13 @@
+from __future__ import unicode_literals
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class ErrorLoggingMiddleware(object):
+    def process_exception(self, request, exception):
+        logger.exception(
+            'Exception caught by request middleware; %s, %s', request,
+            exception
+        )