message: Add difference between ModelType and ReturnModelType to docs
  returnModelType(gh-page): add difference between ModelType and ReturnModelType
  fixes typegoose/typegoose#40
diff: @@ -4,12 +4,14 @@ redirect_from:
  - /docs/types/returnmodeltype
  ---
  -The Type `ReturnModelType<T>` is the type used to have type infomation for a model with Class functions
  +The Type `ReturnModelType<T>` is the type used to have type infomation for a class converted to an mongoose Model
  --> It is the logical 'AND' of `mongoose.Model<DocumentType<T>>` and `T`
  +-> It is the logical `AND` of `mongoose.Model<DocumentType<T>>` and `T`
  Note: It has to be always with `typeof Class`, otherwise it will not work
  +Note: This type should always be used over (the now internal) `ModelType`
  +
  ## Example
  ```ts
  @@ -22,3 +24,8 @@ class Kitten {
  }
  }
  ```
  +
  +## Difference to ModelType
  +
  +`ModelType` is the logical `AND` of `mongoose.Model<DocumentType<T>>` and `T` where as `ReturnModelType` is an extension to `ModelType`: `ModelType<InstanceType<U>> & U`
  +<!--I (hasezoey) dont know how the types worked there, and because ModelType was lacking some types i tried some things and came to this, but dont know what exactly it does-->
  