PlayerSetup.cs

using UnityEditor;
using UnityEngine;

// By B0N3head

// This script, although readable was not created out to be super readable for beginners.
// Its just for setup and is not used during gameplay
[CustomEditor(typeof(PlayerMovement))]
public class PlayerSetup : Editor
{
    string dialogTitle = "Player Movement Setup v1.1", dialogYes = "Yeah", dialogNo = "No thanks";

    public override void OnInspectorGUI()
    {
        DrawDefaultInspector();
        PlayerMovement pmvmt = (PlayerMovement)target;
        GUILayout.Space(10);
        if (GUILayout.Button("Setup Player & World"))
        {
            if (EditorUtility.DisplayDialog(
                    dialogTitle,
                    "Would you like me to set custom world physics for you?\n\n" +
                    "This changes the gravity\n" +
                    "If this is a pre-existing project please use caution, it will change how anything using physics moves",
                    dialogYes,
                    dialogNo
            ))
            {
                Physics.gravity = new Vector3(0, -19F, 0);
                Debug.Log("Physics set");
            }

            if (EditorUtility.DisplayDialog(
                    dialogTitle,
                    "Would you like me to create a \"Ground\" tag for you?",
                    dialogYes,
                    dialogNo
            ))
            {
                createTag("Ground");
            }

            pmvmt.setupCharacter();

            EditorUtility.DisplayDialog(
                    dialogTitle,
                    "Character all setup\n\n" +
                    "Please don't forget to set the ground tag to the ground of your level/scenes",
                    "Awesome, will do"
            );
        }
    }


    // Mashup of code from ctwheels & Leslie-Young by B0N3head 
    // Dw about understanding this, it's just a tool for creating tags in editor for unity
    public void createTag(string tagName)
    {
        SerializedObject tagM = new SerializedObject(AssetDatabase.LoadAllAssetsAtPath("ProjectSettings/TagManager.asset")[0]);
        SerializedProperty tagsP = tagM.FindProperty("tags");
        bool found = false;

        if (tagsP.arraySize < 10000)
        {
            for (int i = 0; i < tagsP.arraySize; i++)
            {
                SerializedProperty t = tagsP.GetArrayElementAtIndex(i);
                if (t.stringValue.Equals(tagName))
                {
                    found = true;
                    Debug.Log($"The \"{tagName}\" tag already exists");
                    break;
                }
            }

            if (!found)
            {
                tagsP.InsertArrayElementAtIndex(0);
                SerializedProperty n = tagsP.GetArrayElementAtIndex(0);
                n.stringValue = tagName;
                Debug.Log($"The \"{tagName}\" tag has been added");
                tagM.ApplyModifiedPropertiesWithoutUndo();
            }
        }
    }
}