Add support for raw json template as content and add docs

README.md

@@ -1,2 +1,55 @@
 # reactbot
 A simple [maubot](https://github.com/maubot/maubot) that responds to messages that match predefined rules.
+
+## Config format
+### Templates
+Templates contain the actual event type and content to be sent.
+* `type` - The Matrix event type to send
+* `content` - The event content. Either an object or jinja2 template that produces JSON.
+* `variables` - A key-value map of variables.
+
+Variables are parsed as jinja2 templates and get the maubot event object in `event`.
+
+If the content is a string, it'll be parsed as a jinja2 template and the output
+will be parsed as JSON. The content jinja2 template will get `event` just like
+variable templates, but it will also get all of the variables.
+
+If the content is an object, that object is what will be sent as the content.
+The object can contain variables using a custom syntax: All instances of
+`$${variablename}` will be replaced with the value matching `variablename`.
+This works in object keys and values and list items. If a key/value/item only
+consists of a variable insertion, the variable may be of any type. If there's
+something else than the variable, the variable will be concatenated using `+`,
+which means it should be a string.
+
+### Default flags
+Default regex flags. Most Python regex flags are available.
+See [docs](https://docs.python.org/3/library/re.html#re.A).
+
+Most relevant flags:
+* `i` / `ignorecase` - Case-insensitive matching.
+* `s` / `dotall` - Make `.` match any character at all, including newline.
+* `x` / `verbose` - Ignore comments and whitespace in regex.
+* `m` / `multiline` - When specified, `^` and `$` match the start and end of
+                      line respectively instead of start and end of whole string.
+
+### Rules
+Rules have five fields. Only `matches` and `template` are required.
+* `rooms` - The list of rooms where the rule should apply.
+            If empty, the rule will apply to all rooms the bot is in.
+* `matches` - The regex or list of regexes to match.
+* `template` - The name of the template to use.
+* `variables` - A key-value map of variables to extend or override template variables.
+                Like with template variables, the values are parsed as Jinja2 templates.
+
+The regex(es) in `matches` can either be simple strings containing the pattern,
+or objects containing additional info:
+* `pattern` - The regex to match.
+* `flags` - Regex flags (replaces default flags).
+* `raw` - Whether or not the regex should be forced to be raw.
+
+If `raw` is `true` OR the pattern contains no special regex characters other
+than `^` at the start and/or `$` at the end, the pattern will be considered
+"raw". Raw patterns don't use regex, but instead use faster string operators
+(equality, starts/endwith, contains). Patterns with the `multiline` flag will
+never be converted into raw patterns implicitly.