Rails tag URL showing ugly “%23”

I'm using the gem acts_as_taggable and want to tag using hashtags #. However, in the URL, it looks like this: http://localhost:3000/tags/%23tagname

How can I make it so that it shows as #tagname in the browser URL bar instead of %23?

routes.rb

  get 'tags/:tag', to: 'posts#index', as: :tag

new.html.erb

<%= f.label :tag_list, 'Tags (separated by commas)' %><br/>
<%= f.text_field :tag_list %>

schema.rb

  create_table "taggings", id: :serial, force: :cascade do |t|
    t.integer "tag_id"
    t.string "taggable_type"
    t.integer "taggable_id"
    t.string "tagger_type"
    t.integer "tagger_id"
    t.string "context", limit: 128
    t.datetime "created_at"
    t.index ["context"], name: "index_taggings_on_context"
    t.index ["tag_id", "taggable_id", "taggable_type", "context", "tagger_id", "tagger_type"], name: "taggings_idx", unique: true
    t.index ["tag_id"], name: "index_taggings_on_tag_id"
    t.index ["taggable_id", "taggable_type", "context"], name: "index_taggings_on_taggable_id_and_taggable_type_and_context"
    t.index ["taggable_id", "taggable_type", "tagger_id", "context"], name: "taggings_idy"
    t.index ["taggable_id"], name: "index_taggings_on_taggable_id"
    t.index ["taggable_type"], name: "index_taggings_on_taggable_type"
    t.index ["tagger_id", "tagger_type"], name: "index_taggings_on_tagger_id_and_tagger_type"
    t.index ["tagger_id"], name: "index_taggings_on_tagger_id"
  end

  create_table "tags", id: :serial, force: :cascade do |t|
    t.string "name"
    t.integer "taggings_count", default: 0
    t.index ["name"], name: "index_tags_on_name", unique: true
  end