added support for redmine issue tracker
added support for jira issue tracker
Merge branch 'feature/third-party-trackers', Refer #107
added support for google apps oauth, refer #111
added twitter oauth configuration support
added github oauth configuration support
added OAUTH_ALLOW_SSO configuration option
added OAUTH_BLOCK_AUTO_CREATED_USERS configuration option
Merge branch 'feature/oauth-support'
readme: document JIRA_URL option in the "Available Configuration Options" section