add grid building system

Assets/Prefabs/House.prefab

@@ -11,7 +11,6 @@ GameObject:
   - component: {fileID: 5852600358559839619}
   - component: {fileID: 2080657515599704299}
   - component: {fileID: 95789179383567876}
-  - component: {fileID: 6347999927300409482}
   m_Layer: 0
   m_Name: House
   m_TagString: Untagged
@@ -85,7 +84,7 @@ SpriteRenderer:
   m_SpriteTileMode: 0
   m_WasSpriteAssigned: 1
   m_MaskInteraction: 0
-  m_SpriteSortPoint: 0
+  m_SpriteSortPoint: 1
 --- !u!61 &95789179383567876
 BoxCollider2D:
   m_ObjectHideFlags: 0
@@ -99,31 +98,16 @@ BoxCollider2D:
   m_IsTrigger: 0
   m_UsedByEffector: 0
   m_UsedByComposite: 0
-  m_Offset: {x: 0, y: 0}
+  m_Offset: {x: 2, y: 0}
   m_SpriteTilingProperty:
     border: {x: 0, y: 0, z: 0, w: 0}
-    pivot: {x: 0.5, y: 0.5}
-    oldSize: {x: 4, y: 4.5625}
+    pivot: {x: 0, y: 0}
+    oldSize: {x: 4, y: 5}
     newSize: {x: 4, y: 4.5625}
     adaptiveTilingThreshold: 0.5
     drawMode: 0
     adaptiveTiling: 0
   m_AutoTiling: 0
   serializedVersion: 2
-  m_Size: {x: 4, y: 4.5625}
+  m_Size: {x: 3, y: 1}
   m_EdgeRadius: 0
---- !u!114 &6347999927300409482
-MonoBehaviour:
-  m_ObjectHideFlags: 0
-  m_CorrespondingSourceObject: {fileID: 0}
-  m_PrefabInstance: {fileID: 0}
-  m_PrefabAsset: {fileID: 0}
-  m_GameObject: {fileID: 6244317213382018835}
-  m_Enabled: 1
-  m_EditorHideFlags: 0
-  m_Script: {fileID: 11500000, guid: b98c0e6f554197e4281920fafc6bab25, type: 3}
-  m_Name: 
-  m_EditorClassIdentifier: 
-  area:
-    m_Position: {x: 0, y: 0, z: 0}
-    m_Size: {x: 4, y: 5, z: 1}