Support PUG match

[FlowingSPDG]

// PugMatchData Struct for match table.
type PugMatchData struct {
	// Original columns...
	ID              int           `gorm:"primary_key;column:id" json:"id"`
	UserID          int           `gorm:"column:user_id" json:"user_id"`
	ServerID        int           `gorm:"column:server_id" json:"server_id"`
	Winner          sql.NullInt32 `gorm:"column:winner" json:"winner"`
	Cancelled       bool          `gorm:"column:cancelled" json:"cancelled"`
	StartTime       sql.NullTime  `gorm:"column:start_time" json:"start_time"`
	EndTime         sql.NullTime  `gorm:"column:end_time" json:"end_time"`
	MaxMaps         int           `gorm:"column:max_maps" json:"max_maps"`
	Title           string        `gorm:"column:title" json:"title"`
	SkipVeto        bool          `gorm:"column:skip_veto" json:"skip_veto"`
	APIKey          string        `gorm:"column:api_key" json:"-"`
	VetoMapPool     string        `gorm:"column:veto_mappool" json:"-"`
	VetoMapPoolJSON []string      `gorm:"-" json:"veto_mappool"`
	Team1Score      int           `gorm:"column:team1_score" json:"team1_score"`
	Team2Score      int           `gorm:"column:team2_score" json:"team2_score"`
	Team1String     string        `gorm:"column:team1_string" json:"team1_string"`
	Team2String     string        `gorm:"column:team2_string" json:"team2_string"`
	Forfeit         bool          `gorm:"column:forfeit" json:"forfeit"`
	PluginVersion   string        `gorm:"column:plugin_version" json:"-"`

	// get5-web-go columns...
	CvarsJSON map[string]string `gorm:"-" json:"cvars"`
	Cvars     string            `gorm:"column:cvars" json:"-"`
	SideType  string            `gorm:"column:side_type" json:"side_type"`

	MapStats []MapStatsData `gorm:"ForeignKey:MatchID" json:"-"`
	Server   GameServerData `json:"-"`
}

also should implement features below:

• Match List(scrim only/pug only/both). Both list may need "JOIN" Query.
• Pug create endpoint
• API should identify request from SRCDS is for scrim or pug.
• Winner should be string("team1" | "team2" | "none" )

• I need to add migration file,and delete "is_pug" column in match table

[FlowingSPDG]

NOTE. If implementing it with "JOIN" query goes ugly, I'll do "1st way" that is described at #127 . e.g. FACEIT uses "TEAM_{CAPTAIN-NAME}" team.