Fixes rename_digest_email_to_email_digest migration for PostgreSQL

PostgreSQL uses double quotes to quote columns and expects strings to be
quoted with single quotes. Single quoted strings work both for MySQL and
PostgreSQL.
Merge pull request #372 from dsander/fix-email-digest-agent-migration

Fixes rename_digest_email_to_email_digest migration for PostgreSQL
Update rails to 4.1.1 and a few other gems

Changes in the gems all look minor.
Merge pull request #375 from dsander/gem-updates

Update rails to 4.1.1 and a few other gems
Fix #378 by duplicating the current form and splitting into two actions.
Add an expected event creation time by default
Merge pull request #379 from CloCkWeRX/relayout_user_edit

Fix #378 by duplicating the current form and splitting into two actions.
Merge pull request #380 from CloCkWeRX/fix_mqtt_working

Add an expected event creation time by default
Add omniauth to let huginn consume oauth endpoints

Created a service model which stores external account information.
Created a service controller which kicks off the oauth process and lets
the user manage their external accounts.
Oauthable concern connects a agent to a service and adds a drop down to the
agents edit page.
Added a migration which converts the existing twitter agents to use the
new service model.
Update new agent form to include the service dropdown

When creating a new agent the service dropdown needs to be updated after
switing the agent type. Rendering the whole form and cherry picking just
the needed services dropdown seemed the easierst solution.
Added documentation about how to set up OAuth applications
User#available_services make sure to escape the parameters, added
missing link to the wiki