I am going to create a website which has exactly same as IMDB.com site logic.
Ok. Go for
Eloquent already has the mechanism to handle this relationship reducing your effort of writing code. Defining the proper relation via pivot table will make you much more easier for handling CRUD operation too.
With the second approach you won't be able to handle this using
Eloquent.And again this is not the standard way of creating relationship between tables. Besides you have to manually prepare the name of the movies separated by comma.