Document format of additionalMethods

Which is, simple truthy properties. Closes #1, for now.

README.md

@@ -161,7 +161,24 @@ _TBD: what this means for `*asBuffer` options._
 
 ### `additionalMethods` (object)
 
-Format TBD.
+In the form of:
+
+```js
+{
+ foo: true,
+ bar: true
+}
+```
+
+Which says the db has two methods, `foo` and `bar`, that are not part of the `abstract-leveldown` interface. It might be used like so:
+
+```js
+if (db.supports.additionalMethods.foo) {
+ db.foo()
+}
+```
+
+For future extensibility, the properties of `additionalMethods` should be taken as truthy rather than strictly typed booleans. We may add additional metadata (see [#1](https:/Level/supports/issues/1)).
 
 ## Install
 

index.js

@@ -30,17 +30,6 @@ module.exports = function supports () {
  encodings: manifest.encodings || false,
 
  // Methods that are not part of abstract-leveldown or levelup
- additionalMethods: manifest.additionalMethods || {
- // May look something like:
- // approximateSize: {
- // sync: false,
- // callback: true,
- // promise: false
- // },
- // createWriteStream: {
- // sync: true,
- // writable: true
- // }
- }
+ additionalMethods: manifest.additionalMethods || {}
  })
 }