resolver outside of the class isn't working in SQLAlchemyConnectionField

I've been trying to get this to work for some time and haven't been able to figure it out. I am trying to use a resolver outside of a class using an SQLAlchemyConnectionField. The resolver is called when it is in the class however not when it is outside of the class. I have modified the flask example code to demonstrate this:

```
class Employee(SQLAlchemyObjectType):

class Meta:
model = EmployeeModel
interfaces = (relay.Node, )

favourite_roles = SQLAlchemyConnectionField(Role)

def resolve_favourite_roles(self, args, context, info):
# everyone wants to be a manager
return Role.get_query(Role).filter_by(name='manager')
```
The above code works as expected. for the query:
```
{allEmployees {
edges {
node {
name
favouriteRoles {
edges{
node {
name
}
}
}
}
}
}}
```
It returns:
```
{
"data": {
"allEmployees": {
"edges": [
{
"node": {
"name": "Peter",
"favouriteRoles": {
"edges": [
{
"node": {
"name": "manager"
}
}
]
}
}
},
{
"node": {
"name": "Roy",
"favouriteRoles": {
"edges": [
{
"node": {
"name": "manager"
}
}
]
}
}
},
{
"node": {
"name": "Tracy",
"favouriteRoles": {
"edges": [
{
"node": {
"name": "manager"
}
}
]
}
}
}
]
}
}
}
```
However when I have this code:
```
def resolve_favourite_roles(root, args, context, info):
# everyone wants to be a manager
return Role.get_query(Role).filter_by(name='manager')

class Employee(SQLAlchemyObjectType):

class Meta:
model = EmployeeModel
interfaces = (relay.Node, )

favourite_roles = SQLAlchemyConnectionField(Role, resolver=resolve_favourite_roles)
```
This is the result.
```
{
"data": {
"allEmployees": {
"edges": [
{
"node": {
"name": "Peter",
"favouriteRoles": {
"edges": [
{
"node": {
"name": "manager"
}
},
{
"node": {
"name": "engineer"
}
}
]
}
}
},
{
"node": {
"name": "Roy",
"favouriteRoles": {
"edges": [
{
"node": {
"name": "manager"
}
},
{
"node": {
"name": "engineer"
}
}
]
}
}
},
{
"node": {
"name": "Tracy",
"favouriteRoles": {
"edges": [
{
"node": {
"name": "manager"
}
},
{
"node": {
"name": "engineer"
}
}
]
}
}
}
]
}
}
}
```
The resolver function is not being called when it is outside of the class.

Any help is appreciated.

從修改後的 Flask 範例開始，將類別解析器與傳遞給 SQLAlchemyConnectionField 的解析器進行比較。追蹤欄位的解析方式，並確認外部解析器已被呼叫；完成的標準是查詢只回傳 manager 角色，就像正常運作的類別式範例一樣。

由索引模型根據 Issue 內容生成。