Made some progress

db/migrate/20160222122600_create_stream_entries.rb

@@ -0,0 +1,11 @@
+class CreateStreamEntries < ActiveRecord::Migration
+  def change
+    create_table :stream_entries do |t|
+      t.integer :account_id
+      t.integer :activity_id
+      t.string :activity_type
+
+      t.timestamps null: false
+    end
+  end
+end