Fixed migrate error on mysql

Author: sanak

db/migrate/20170831050051_create_text_blocks.rb

@@ -3,7 +3,7 @@ def change
     create_table :text_blocks do |t|
       t.string :name
       t.text :text
-      t.references :project, index: true, foreign_key: true
+      t.references :project, index: true, foreign_key: true, type: :integer
 
       t.timestamps null: false
     end