[WIP] add markdown getting started page to api docs (#752)

* add markdown getting started page to api docs. TODO section 3

* Update getting-started.md

doc/api/api.raml

@@ -4,6 +4,12 @@ title: Metamaps
 version: v2.0
 baseUri: https://metamaps.cc/api/v2
 mediaType: application/json
+protocols: [ HTTPS ]
+documentation:
+  - title: Getting Started
+    content: !include pages/getting-started.md
+  - title: Endpoints
+    content: ""
 
 securitySchemes:
   oauth_2_0: !include securitySchemes/oauth_2_0.raml

doc/api/pages/getting-started.md

@@ -0,0 +1,81 @@
+[Skip ahead to the endpoints.](#endpoints)
+
+There are three ways to log in: cookie-based authentication, token-based authentication, or OAuth 2.
+
+### 1. Cookie-based authentication
+
+One way to access the API is through your browser. Log into metamaps.cc normally, then browse manually to https://metamaps.cc/api/v2/user/current. You should see a JSON description of your own user object in the database. You can browse any GET endpoint by simply going to that URL and appending query parameters in the URI.
+
+To run a POST or DELETE request, you can use the Fetch API. See the example in the next section.
+
+### 2. Token-based authentication
+
+If you are logged into the API via another means, you can create a token. Once you have this token, you can append it to a request. For example, opening a private window in your browser and browsing to `https://metamaps.cc/api/v2/user/current?token=...token here...` would show you your current user, even without logging in by another means.
+
+To get a list of your current tokens, you can log in using cookie-based authentication and run the following fetch request in your browser console (assuming the current tab is on some page within the `metamaps.cc` website.
+
+```
+fetch('/api/v2/tokens', {
+  method: 'GET',
+  credentials: 'same-origin' // needed to use the cookie-based auth
+}).then(response => {
+  return response.json()
+}).then(console.log).catch(console.error)
+```
+
+If this is your first time accessing the API, this list wil be empty. You can create a token using a similar method:
+
+```
+fetch('/api/v2/tokens', {
+  method: 'POST',
+  credentials: 'same-origin'
+}).then(response => {
+  return response.json()
+}).then(console.log).catch(console.error)
+```
+
+`payload.data.token` will contain a string which you can use to append to requests to access the API from anywhere.
+
+### 3. OAuth 2 Authentication
+
+We use a flow for Oauth 2 authentication called Authorization Code. It basically consists of an exchange of an `authorization` token for an `access token`. For more detailed info, check out the [RFC spec here](http://tools.ietf.org/html/rfc6749#section-4.1)
+
+The first step is to register your client app.
+
+#### Registering the client
+
+Set up a new client in `/oauth/applications/new`. For testing purposes, you should fill in the redirect URI field with `urn:ietf:wg:oauth:2.0:oob`. This will tell it to display the authorization code instead of redirecting to a client application (that you don't have now).
+
+#### Requesting authorization
+
+To request the authorization token, you should visit the `/oauth/authorize` endpoint. You can do that either by clicking in the link to the authorization page in the app details or by visiting manually the URL:
+
+```
+http://metamaps.cc/oauth/authorize?client_id=YOUR_CLIENT_ID&redirect_uri=urn:ietf:wg:oauth:2.0:oob&response_type=code
+```
+
+Once you are there, you should sign in and click on `Authorize`.
+You will then see a response that contains your "authorization code", which you need to exchange for an access token.
+
+#### Requesting the access token
+
+To request the access token, you should use the returned code and exchange it for an access token. To do that you can use any HTTP client. Here's an example with `fetch`
+
+```javascript
+fetch('https://metamaps.cc/oauth/token?client_id=THE_ID&client_secret=THE_SECRET&code=RETURNED_CODE&grant_type=authorization_code&redirect_uri=urn:ietf:wg:oauth:2.0:oob', {
+  method: 'POST',
+  credentials: 'same-origin'
+}).then(response => {
+  return response.json()
+}).then(console.log).catch(console.error)
+
+# The response will be like
+{
+ "access_token": "de6780bc506a0446309bd9362820ba8aed28aa506c71eedbe1c5c4f9dd350e54",
+ "token_type": "bearer", 
+ "expires_in": 7200,
+ "refresh_token": "8257e65c97202ed1726cf9571600918f3bffb2544b26e00a61df9897668c33a1"
+}
+```
+
+You can now make requests to the API with the access token returned.