Import feature for following/blocking lists (addresses #62, #177, #201, #454)

db/migrate/20170330163835_create_imports.rb

@@ -0,0 +1,11 @@
+class CreateImports < ActiveRecord::Migration[5.0]
+  def change
+    create_table :imports do |t|
+      t.integer :account_id, null: false
+      t.integer :type, null: false
+      t.boolean :approved
+
+      t.timestamps
+    end
+  end
+end