E-learning: Add courses routes, index, and new form

[faithngetich]

Feature: Courses As a site teacher In order to be able to teach things I would like to create courses

Scenario: Creating a new course Given I have logged in And I am on the "courses" page When I click the "New Course" button Then I should see "Creating a new Course" And I should see a form with: | Field | | Title | | Description | | Slack channel name |

Snippets (if we decide to use simple_form gem):

// Gemfile gem 'simple_form'

// Console bundle install rails generate simple_form:install

// Any form can look something like = simple_form_for @course do |f| = f.error_notification = f.error_notification message: f.object.errors[:base].to_sentence if f.object.errors[:base].present? = f.input :title = f.label :description = f.rich_text_area :description /= f.submit 'Save' = f.button :submit