Add Bitbucket connector

Documentation/connectors/bitbucket.md

@@ -0,0 +1,30 @@
+# Authentication through Bitbucket Cloud
+
+## Overview
+
+One of the login options for dex uses the Bitbucket OAuth2 flow to identify the end user through their Bitbucket account.
+
+When a client redeems a refresh token through dex, dex will re-query Bitbucket to update user information in the ID Token. To do this, __dex stores a readonly Bitbucket access token in its backing datastore.__ Users that reject dex's access through Bitbucket will also revoke all dex clients which authenticated them through Bitbucket.
+
+## Configuration
+
+Register a new OAuth consumer with [Bitbucket](https://confluence.atlassian.com/bitbucket/oauth-on-bitbucket-cloud-238027431.html) ensuring the callback URL is `(dex issuer)/callback`. For example if dex is listening at the non-root path `https://auth.example.com/dex` the callback would be `https://auth.example.com/dex/callback`.
+
+The following is an example of a configuration for `examples/config-dev.yaml`:
+
+```yaml
+connectors:
+- type: bitbucket
+  # Required field for connector id.
+  id: bitbucket
+  # Required field for connector name.
+  name: Bitbucket
+  config:
+    # Credentials can be string literals or pulled from the environment.
+    clientID: $BITBUCKET_CLIENT_ID
+    clientSecret: BITBUCKET_CLIENT_SECRET
+    redirectURI: http://127.0.0.1:5556/dex/callback
+    # Optional teams, communicated through the "groups" scope.
+    teams:
+    - my-team
+```