message: Add: metamask instance `detect` documentation
diff: @@ -15,6 +15,7 @@ When building with `NODE_ENV=production` all output will be silenced.
  * Wallet
  * Metamask
  * [`open`](#open)
  + * [`detect`](#detect)
  ### Metmask
  @@ -72,3 +73,22 @@ import { open } from 'colony-wallet/metamask';
  const wallet = await open();
  ```
  +
  +### `detect`
  +
  +```js
  +await detect();
  +```
  +
  +This is a helper method to detect if the Metamask injected `web3` proxy instance is available. It's not necessary for you to use since it's baked into the library, it's just exposed here for convenience.
  +
  +This method returns a `Promise` which, after resolving, it will `return` only return `true`, if the Metamask instance is available and can be interacted with _(not locked)_. Otherwise it will `throw` an Error with the specific problem it encountered.
  +
  +**Usage examples:**
  +
  +Open the metamask wallet:
  +```js
  +import { detect as isMetamaskAvailable } from 'colony-wallet/metamask';
  +
  +await isMetamaskAvailable();
  +```
  