ruby on rails - Can't get search on a date range based on created_at working -

i trying add ability search records based on from/to date range.

class search < activerecord::base    has_many :documents    # code below sets scopes based on search/input form entries.    def search_documents      documents = document.all      documents = documents.where("subject ?", "%#{subject}%") if subject.present?     documents = documents.where("body ?", "%#{text}%") if text.present?     documents = documents.joins(:category).where("categories.name ?", "%#{category}%") if category.present?     documents = documents.joins(:author).where("authors.name ?", "%#{author}%") if author.present?     documents = documents.joins(:reviewer).where("reviewers.name ?", "%#{reviewer}%") if reviewer.present?      documents = documents.where("created_at >= ?", "{from_date}") if from_date.present? 

the first 5 lines work fine. problem last line date. way now, no records. i.e database has records created_at date of 10/5/2015 through 10/21/2015, if enter 10/15/2015, no records though there records created after date.

from date comes form model. schema is:

t.date     "from_date" 

you need re write code this

documents = documents.where("created_at >= ?", from_date) if from_date.present?