Circle.md

+Circle original implementation. Provides an easy interface to manipulate, save and restore, circle-like values from the database. Works very similar to the `ActiveRecord::Point`, but for a list of 1 point and 1 radius data (`x`, `y`, and `r`). [PostgreSQL Docs](https://www.postgresql.org/docs/9.6/datatype-geometric.html#DATATYPE-CIRCLE)
+
+# How it works
+
+### Migration
+
+Just set the type of the column as `circle` when creating a table.
+```ruby
+create_table "region" do |t|
+  t.string "title", null: false
+  t.circle "area"
+end
+```
+
+### Using it
+
+The column is automatically identified and its value turned into what is defined on [`geometry.circle_class`](https://github.com/crashtech/torque-postgresql/wiki/Configuring#geometry.circle_class) or into a `Torque::PostgreSQL::Circle`. 
+
+This original implementation provides a couple of methods:
+```ruby
+region = Region.new
+region.area.x
+region.area.y
+region.area.r
+region.area.radius   # Same as r
+region.area.center   # Which will return a point for the center
+```
+
+The value can be set in some different manners:
+
+```ruby
+region.area = '10,10,5'
+region.area = '[10,10],5'
+region.area = '<(10,10),5>'
+region.area = [10,10,5]
+region.area = [[10,10],5]
+region.area = { x: 10, y: 10, r: 5 }
+```
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