Revert "Revised HMT, but does not *work*. Also, replaced category images with SVG files, also non-functional. Yay."

This reverts commit abceb49907baa253fff3c96c6ba4f0be2c26bfad.
Revert "Add planets/galaxies lab classwork."

This reverts commit 7c72b41af82adfb072d1b13c4914c57e29bdbba1.
Revert "Change join table name, now site functioning again."

This reverts commit c4fbc2223b477da0847ad111db61081038fa316e.
Revert "Add active link from class and setup for has_many through."

This reverts commit 368a720381a274539053e2c70a37808d716c8ff7.
Start to fix HTM.
Add changes to seeds and db.
Fix has_many :through.
Apply HMT to Ingredients views.
Merge with has-many-through and add active link functionality.
Add styling for active link.
Add svg icons.
Add User model and users table.
Add users controller.
Add users resource routes for index, new and create views.
Add bcrypt gem and add has_secure_password method and password validations to user model.
Add new user form.
Add create user functionality and users index view.
Add sessions controller.
Add new session/login view.
Add login/logout functionality.