add reader README.md

docs/DATA_FORMATS_INPUT.md

@@ -655,7 +655,9 @@ For more information about the dropwizard json format see
 ```
 
 #### Grok
-Parse logstash-style "grok" patterns:
+Parse logstash-style "grok" patterns. Patterns can be added to patterns, or custom patterns read from custom_pattern_files.
+
+#### Grok Configuration:
 ```toml
   [inputs.reader]
     ## This is a list of patterns to check the given log file(s) for.

plugins/inputs/reader/README.md

@@ -0,0 +1,21 @@
+# Reader Input Plugin
+
+The Reader Plugin updates a list of files every interval and parses the data inside.  
+This plugin can parse any "data_format" formats.
+
+### Configuration:
+```toml
+## Files to parse each interval.
+## These accept standard unix glob matching rules, but with the addition of
+## ** as a "super asterisk". ie:
+##   /var/log/**.log     -> recursively find all .log files in /var/log
+##   /var/log/*/*.log    -> find all .log files with a parent dir in /var/log
+##   /var/log/apache.log -> only tail the apache log file
+files = ["/var/log/apache/access.log"]
+
+## The dataformat to be read from files
+## Each data format has its own unique set of configuration options, read
+## more about them here:
+## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_INPUT.md
+data_format = ""
+```