fix style issues

apps/explorer/lib/explorer/chain/smart_contract.ex

@@ -213,7 +213,7 @@ defmodule Explorer.Chain.SmartContract do
     field(:constructor_arguments, :string)
     field(:evm_version, :string)
     field(:optimization_runs, :integer)
-    embeds_many :external_libraries, ExternalLibrary
+    embeds_many(:external_libraries, ExternalLibrary)
     field(:abi, {:array, :map})
 
     has_many(

apps/explorer/lib/explorer/chain/smart_contract/external_library.ex

@@ -1,8 +1,12 @@
 defmodule Explorer.Chain.SmartContract.ExternalLibrary do
+  @moduledoc """
+  The representation of an external library that was used for a smart contract.
+  """
+
   use Ecto.Schema
 
   embedded_schema do
-    field :name
-    field :address_hash
+    field(:name)
+    field(:address_hash)
   end
 end

apps/explorer/priv/repo/migrations/20190709103104_add_external_libraries_to_smart_contracts.exs

@@ -3,11 +3,11 @@ defmodule Explorer.Repo.Migrations.AddExternalLibrariesToSmartContracts do
 
   def change do
     alter table(:smart_contracts) do
-      remove :external_libraries
+      remove(:external_libraries)
     end
 
     alter table(:smart_contracts) do
-      add :external_libraries, {:array, :map}, default: []
+      add(:external_libraries, {:array, :map}, default: [])
     end
   end
 end