*: use coreos postgres image for travis ci

Moved postgres image from personal account to quay.io/coreos.

*: add functional tests to travis config (WIP)

Godeps: update github.com/coreos/go-oidc

connector: document Connector and ConnectorConfig interfaces

don't call go-bindata on every build

Add go generate rule to generate migration assets.

*: add .travis.yml and status badge to README

closes #203

cmd, db: verify at least one secret is passed to --key-secrets

server: fix tests

Passing an empty list to the overlord or worker's --key-secrets
flag currently causes an out of range panic. Always check to ensure
there's at least one element passed.

Fixes #130
Fixes #217

In #210 a field name in the provider config was corrected. However
the old, and incorrect, value was hard coded in the tests. This
change updates the test case to hold the correct field name.

There are no other references to the old name in dex or its
vendored packages.

static: use --issuer-name as title for public facing pages

Godeps: update github.com/coreos/go-oidc/oidc to fix field name

docs: fix invocation of test-functional

Release scripts

Closes #142

Correct provider config field "id_token_alg_values_supported" to
"id_token_signing_alg_values_supported".

Fixes #212

Godeps: update coreos/go-oidc to include OIDC race condition fixes

Update github.com/coreos/go-oidc/... to include coreos/go-oidc#17
which fixes a race condition in the OIDC connector.

connector: github and bitbucket oauth2 connectors added

db: strconv.ParseInt specify base 10

closes #99

Add icons and styles for github and bitbucket buttons.

Add bitbucket implementation of oauth2 connector.

Add interface for oauth2 connectors and a github implementation.

Update Godeps to include:

* coreso/go-oidc#24: reqiured for GitHub connector
* coreso/go-oidc#26: better error messages when connectors are misconfigured

db: fixed missing return statement GetConnectorByID

Added missing err return introduced by #199

api: validate local connector existence before creating user

Add ConnectorConfigRepo to UserManager. When trying to create a
RemoteIdentity, validate that the connector ID exists.

Fixes #198