Content: add contents to Game

[Virako]

Create API REST for Content:

• Create serializers and use deserializers for create/update
• Create factories for tests with factory-boy
• For create content, there are two ways:

content-way1: {   // Thing or Character already exist in DB
    game: game_pk, // int,
    position: (lat, lng),  // tuple(float, float),
    content_type: "Item/Knowledge/Rol/Player/NPC", // str
    content_id: item_id, rol_id, ..., // id
}

content-way2: {  // Thing or Character not exist and you should create
    game: game_pk, // int,
    position: (lat, lng),  // tuple(float, float),
    content_type: "Item/Knowledge/Rol/Player/NPC", // str
    content: {
        // Thing or Character serializered
    },  
    content_id: item_id, rol_id, ... (when content will be created), // id
}

• Create contents inside games:

When we are creating a game, we should be able to create contents inside game. There are two ways for create:

game-way1: {  // Thing or Character already exist
            'title': 'Example',
            'start': '2018-02-04T07:28:12.546030+00:00',
            'preferences': {
                'vision_distance': 100,
                'meeting_distance': 20,
                'visible_character': True
            }
            'contents': [
                {
                    game: not neccesary you should use this game,
                    position: (lat, lng),  // tuple(float, float),
                    content_type: "Item/Knowledge/Rol/Player/NPC", // str
                    content_id: item_id, rol_id, ..., // id
                },
            ],
}

game-way2: {  // Thing or Character not exist and you should create
            'title': 'Example',
            'start': '2018-02-04T07:28:12.546030+00:00',
            'preferences': {
                'vision_distance': 100,
                'meeting_distance': 20,
                'visible_character': True
            }
            'contents': [
                {
                    game: not neccesary you should use this game,
                    position: (lat, lng),  // tuple(float, float),
                    content_type: "Item/Knowledge/Rol/Player/NPC", // str
                    content: {
                        // Thing or Character serializered
                    },  
                    content_id: item_id, rol_id, ..., // id
                },
            ],
}

[Virako]

Done: Content API

I had done some changes:

• content_type is pk instead str
• position is a dict: {"latitude": float, "longitude": float} instead tuple (float, float)

Pending: Game with contents

[Virako]

PR: done #18