Remove get allowance endpoint (#35)

The GET /user/:userId endpoint already does this operation

Closes #10

Reviewed-on: #35

common/api.yaml

@@ -60,29 +60,6 @@ paths:
           description: The users could not be found.
 
   /user/{userId}/allowance:
-    get:
-      summary: Gets the allowance breakdown of a user
-      parameters:
-        - in: path
-          name: userId
-          description: The user ID
-          required: true
-          schema:
-            type: integer
-      responses:
-        200:
-          description: Information about the allowance of the user
-          content:
-            application/json:
-              schema:
-                type: object
-                properties:
-                  allowance:
-                    type: integer
-                    description: The total allowance value of the user, in cents.
-                  goals:
-                    type: array
-                    $ref: "#/components/schemas/goal"
     post:
       summary: Updates the allowance of a user
       parameters: