simplify and structure migration code, split big function to small functions

Author: liveforeverx

.gitignore

@@ -3,3 +3,4 @@
 /deps
 erl_crash.dump
 *.ez
+mix.lock

README.md

@@ -2,3 +2,50 @@ EctoMigrate
 ===========
 
 **TODO: Add description**
+
+```elixir
+
+# Configuration for Repo, only for iex try taste, please use supervisor in your application
+:application.set_env(:example, Repo, [adapter: Ecto.Adapters.MySQL, database: "example", username: "root"])
+defmodule Repo, do: (use Ecto.Repo, otp_app: :example)
+Repo.start_link
+import Ecto.Query
+
+defmodule Weather do # is for later at now
+  use Ecto.Model
+
+  schema "weather" do
+    field :city
+    field :temp_lo, :integer
+    field :temp_hi, :integer
+    field :prcp,    :float, default: 0.0
+  end
+end
+
+Ecto.Migration.Auto.migrate(Repo, Weather)
+
+%Weather{city: "Berlin", temp_lo: 20, temp_hi: 25} |> Repo.insert
+Repo.all(from w in Weather, where: w.city == "Berlin")
+
+```
+
+Lets redefine the same model in a shell and migrate it
+
+```elixir
+
+defmodule Weather do # is for later at now
+  use Ecto.Model
+
+  schema "weather" do
+    field :city
+    field :temp_lo, :integer
+    field :temp_hi, :integer
+    field :prcp,    :float, default: 0.0
+    field :wind,    :float, default: 0.0
+  end
+end
+
+Ecto.Migration.Auto.migrate(Repo, Weather)
+Repo.all(from w in Weather, where: w.city == "Berlin")
+
+```