Create tagging system (#792)

* Repro

* Fix

* Update signage

* Create tagging system

* Add tags to transaction imports

* Build tagging UI

* Cleanup

* More cleanup

app/models/family.rb

@@ -1,5 +1,6 @@
 class Family < ApplicationRecord
   has_many :users, dependent: :destroy
+  has_many :tags, dependent: :destroy
   has_many :accounts, dependent: :destroy
   has_many :transactions, through: :accounts
   has_many :imports, through: :accounts

app/models/import.rb

@@ -111,16 +111,24 @@ class Import < ApplicationRecord
     def generate_transactions
       transactions = []
       category_cache = {}
+      tag_cache = {}
 
       csv.table.each do |row|
-        category_name = row["category"]
+        category_name = row["category"].presence
+        tag_strings = row["tags"].presence&.split("|") || []
+        tags = []
 
-        category = category_cache[category_name] ||= account.family.transaction_categories.find_or_initialize_by(name: category_name) if row["category"].present?
+        tag_strings.each do |tag_string|
+          tags << tag_cache[tag_string] ||= account.family.tags.find_or_initialize_by(name: tag_string)
+        end
+
+        category = category_cache[category_name] ||= account.family.transaction_categories.find_or_initialize_by(name: category_name)
 
         txn = account.transactions.build \
           name: row["name"].presence || FALLBACK_TRANSACTION_NAME,
           date: Date.iso8601(row["date"]),
           category: category,
+          tags: tags,
           amount: BigDecimal(row["amount"]) * -1, # User inputs amounts with opposite signage of our internal representation
           currency: account.currency
 
@@ -144,12 +152,16 @@ class Import < ApplicationRecord
         key: "category",
         label: "Category"
 
+      tags_field = Import::Field.new \
+        key: "tags",
+        label: "Tags"
+
       amount_field = Import::Field.new \
         key: "amount",
         label: "Amount",
         validator: ->(value) { Import::Field.bigdecimal_validator(value) }
 
-      [ date_field, name_field, category_field, amount_field ]
+      [ date_field, name_field, category_field, tags_field, amount_field ]
     end
 
     def define_column_mapping_keys

app/models/tag.rb

@@ -0,0 +1,25 @@
+class Tag < ApplicationRecord
+  belongs_to :family
+  has_many :taggings, dependent: :destroy
+  has_many :transactions, through: :taggings, source: :taggable, source_type: "Transaction"
+
+  validates :name, presence: true, uniqueness: { scope: :family }
+
+  scope :alphabetically, -> { order(:name) }
+
+  COLORS = %w[#e99537 #4da568 #6471eb #db5a54 #df4e92 #c44fe9 #eb5429 #61c9ea #805dee #6ad28a]
+
+  UNCATEGORIZED_COLOR = "#737373"
+
+  def replace_and_destroy!(replacement)
+    transaction do
+      raise ActiveRecord::RecordInvalid, "Replacement tag cannot be the same as the tag being destroyed" if replacement == self
+
+      if replacement
+        taggings.update_all tag_id: replacement.id
+      end
+
+      destroy!
+    end
+  end
+end

app/models/tagging.rb

@@ -0,0 +1,4 @@
+class Tagging < ApplicationRecord
+  belongs_to :tag
+  belongs_to :taggable, polymorphic: true
+end

app/models/transaction.rb

@@ -5,6 +5,9 @@ class Transaction < ApplicationRecord
   belongs_to :category, optional: true
   belongs_to :merchant, optional: true
 
+  has_many :taggings, as: :taggable, dependent: :destroy
+  has_many :tags, through: :taggings
+
   validates :name, :date, :amount, :account, presence: true
 
   monetize :amount