added the last two models

app/controllers/credentials_controller.rb

@@ -0,0 +1,70 @@
+class CredentialsController < ApplicationController
+  before_action :set_credential, only: %i[ show edit update destroy ]
+
+  # GET /credentials or /credentials.json
+  def index
+    @credentials = Credential.all
+  end
+
+  # GET /credentials/1 or /credentials/1.json
+  def show
+  end
+
+  # GET /credentials/new
+  def new
+    @credential = Credential.new
+  end
+
+  # GET /credentials/1/edit
+  def edit
+  end
+
+  # POST /credentials or /credentials.json
+  def create
+    @credential = Credential.new(credential_params)
+
+    respond_to do |format|
+      if @credential.save
+        format.html { redirect_to credential_url(@credential), notice: "Credential was successfully created." }
+        format.json { render :show, status: :created, location: @credential }
+      else
+        format.html { render :new, status: :unprocessable_entity }
+        format.json { render json: @credential.errors, status: :unprocessable_entity }
+      end
+    end
+  end
+
+  # PATCH/PUT /credentials/1 or /credentials/1.json
+  def update
+    respond_to do |format|
+      if @credential.update(credential_params)
+        format.html { redirect_to credential_url(@credential), notice: "Credential was successfully updated." }
+        format.json { render :show, status: :ok, location: @credential }
+      else
+        format.html { render :edit, status: :unprocessable_entity }
+        format.json { render json: @credential.errors, status: :unprocessable_entity }
+      end
+    end
+  end
+
+  # DELETE /credentials/1 or /credentials/1.json
+  def destroy
+    @credential.destroy
+
+    respond_to do |format|
+      format.html { redirect_to credentials_url, notice: "Credential was successfully destroyed." }
+      format.json { head :no_content }
+    end
+  end
+
+  private
+    # Use callbacks to share common setup or constraints between actions.
+    def set_credential
+      @credential = Credential.find(params[:id])
+    end
+
+    # Only allow a list of trusted parameters through.
+    def credential_params
+      params.require(:credential).permit(:email, :password)
+    end
+end