Added AutoRespond documentation

docs/docs/autorespond.md

@@ -1,2 +1,29 @@
 ## AutoRespond
-(to be written later)
+
+AutoRespond is a component that exists exclusively to allow your bot to respond to certain text triggers. An AutoRespond *definition* takes one or more regular expression patterns, a response string, and optionally several other options for adjusting the definition's behavior.
+
+Although it is possible to create auto-response rules using AutoMod, defining them in AutoRespond allows you to not have to worry about adding extra configuration to ensure it works properly for all users.
+
+Sample AutoRespond definitions:
+```
+"Help command": {
+    "regex": "^!help$",
+    "reply": "You can't be helped. Try again in 45 minutes.",
+    "ratelimit": 2700
+},
+"Spam trigger": {
+    "regex": [
+        "spam post",
+        "dumb",
+        "productive conversation"
+    ],
+    "exec": "python /home/autospam.py"
+}
+```
+
+The following is a list of accepted members within an AutoRespond definition:
+* regex (*string* or *string array*) - **Required.** Regular expression pattern(s) that will invoke the response.
+* reply *(string)* - The message to send out to the channel in which the response was invoked.
+* exec *(string)* - Command line path and optional parameters to an external program. The program's output will be sent to the channel in which the response was invoked.
+  * It is **required** to have one of either *reply* or *exec* in a definition.
+* ratelimit *(integer)* - The amount of time in seconds in which the response may not be triggered again within the same channel. Defaults to 20.