message: Add: `metamask` provider api docs section
diff: @@ -4,11 +4,14 @@ This docs serve to outline the API format and methods provided by `colony-wallet
  #### Console output
  -In `development` mode there will be a number of warnings or errors outputted verbosely to the console. When building with `NODE_ENV=production` all output will be silenced.
  +In `development` mode there will be a number of warnings or errors outputted verbosely to the console.
  +
  +When building with `NODE_ENV=production` all output will be silenced.
  ## Contents
  * [Providers](#Providers)
  + * [`metamask`](#metamask)
  * [`etherscan`](#etherscan)
  * [`infura`](#infura)
  @@ -18,6 +21,23 @@ Create a connection to an Ethereum blockchain. This is achieved differently by t
  HTTP API endpoint for _etherscan_ and _infura_, injected into the webpage in the case of _metamask_, or local RPC connection in the case of _localhost_.
  +### `metamask`
  +
  +```js
  +metamask([network: string])
  +```
  +
  +This provider method takes just an optional `network` name as string _(defaults to 'homestead')_ and will use the in-page `Web3` provider injected by the [Metamask extension](https://github.com/MetaMask/metamask-extension), if available.
  +
  +```js
  +import { metamask } from 'colony-wallet/providers';
  +
  +const provider = metamask('homestead'); // { chainId: '', ensAddress: '', ... }
  +
  +// Or just use the defaults if you just want to go on mainnet.
  +const providerDefaults = metamask();
  +```
  +
  ### `etherscan`
  ```js
  